Abstract
We evaluated weed competition effects on the N economy of field pea ( Pisum sativum L.) and the subsequent crop to address the paucity of such information. Plots were seeded to pea, canola ( Brassica napus L.) and barley ( Hordeum vulgare L.) in 1997 and 1998. Weeds, augmented by cross‐seeding experimental plots with oat (Avena sativa L.), were removed with herbicides one and four weeks after crop emergence (WAE). The subsequent barley crop received 0 or 6 g N m −2 Mean percentage of N derived from the atmosphere (%Ndfa) for the 2 yr, estimated by 15 N isotopic dilution, was 81% for the 4‐WAE treatment and 51% for the 1‐WAE treatment, indicating that a pea plant subjected to greater weed competition derived more of its N from symbiotic fixation. Total N fixed by pea was not affected by the time of weed removal, however, and total N uptake and seed yield were greater with early weed removal due to less competition for soil N. Early weed removal resulted in net N export in pea seeds (because of higher production) while later weed removal resulted in gains of 1.1 to 1.3 g N m −2 However, time of weed removal during pea cultivation had no effect on the yield or N uptake of the subsequent barley crop. Higher barley yield and N uptake following pea than following barley were mostly the result of greater N availability. Nitrogen fertilization benefited the subsequent barley regardless of preceding crop type.
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Claims 11
Claim · model-written summary
Later weed removal increased the share of pea nitrogen derived from fixation from 51% to 81%.
Verbatim
e0“Mean percentage of N derived from the atmosphere (%Ndfa) for the 2 yr, estimated by 15 N isotopic dilution, was 81% for the 4‐WAE treatment and 51% for the 1‐WAE treatment”
t0“Field Pea”
Claim · model-written summary
Total nitrogen fixed by pea was unaffected by weed removal timing.
- Taxon
- pea
Lathyrus oleraceuse0 - Treatment
- time of weed removale0
- Outcome
- Total N fixede0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total N fixed by pea was not affected by the time of weed removal”
Claim · model-written summary
Early weed removal increased total nitrogen uptake in pea.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- early weed removale0
- Outcome
- total N uptakee0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total N uptake and seed yield were greater with early weed removal due to less competition for soil N”
t0“Field Pea”
Claim · model-written summary
Early weed removal increased pea seed yield.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- early weed removale0
- Outcome
- seed yielde0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total N uptake and seed yield were greater with early weed removal due to less competition for soil N”
t0“Field Pea”
Claim · model-written summary
Early weed removal caused net nitrogen export in pea seeds.
- Taxon
- peaLathyrus oleraceuse0
- Treatment
- Early weed removale0
- Outcome
- net N export in pea seedse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Early weed removal resulted in net N export in pea seeds”
Claim · model-written summary
Later weed removal produced a nitrogen gain of 1.1 to 1.3 g N m −2.
- Taxon
- peaLathyrus oleraceust0
- Treatment
- later weed removale0
- Outcome
- gainse0
- Direction
- gainse0
- Value
- 1.1 to 1.3 g N m −2e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“later weed removal resulted in gains of 1.1 to 1.3 g N m −2”
t0“Field Pea”
Claim · model-written summary
Pea weed removal timing did not affect yield of the subsequent barley crop.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree0 - Treatment
- time of weed removal during pea cultivatione0
- Outcome
- yielde0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“time of weed removal during pea cultivation had no effect on the yield or N uptake of the subsequent barley crop”
Claim · model-written summary
Pea weed removal timing did not affect nitrogen uptake of the subsequent barley crop.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- time of weed removal during pea cultivatione0
- Outcome
- N uptakee0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“time of weed removal during pea cultivation had no effect on the yield or N uptake of the subsequent barley crop”
Claim · model-written summary
Barley yield was higher after pea than after barley.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- following peae0
- Outcome
- barley yielde0
- Direction
- Highere0
- Comparator
- following barleye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher barley yield and N uptake following pea than following barley were mostly the result of greater N availability”
Claim · model-written summary
Barley nitrogen uptake was higher after pea than after barley.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- following peae0
- Outcome
- N uptakee0
- Direction
- Highere0
- Comparator
- following barleye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher barley yield and N uptake following pea than following barley were mostly the result of greater N availability”
Claim · model-written summary
Nitrogen fertilizer benefited subsequent barley regardless of preceding crop.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- Nitrogen fertilizatione0
- Outcome
- subsequent barleye0
- Direction
- benefitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertilization benefited the subsequent barley regardless of preceding crop type”
The same questions in other papers
fertilization · organism · Hordeum vulgare (barley)Positive and negative results
15 papers in the same direction as this paper · 3 in the opposite direction
- no effect
- negative
- no effect
15 papers more in this group
See all 19 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.