Abstract
Abstract Cowpeas [ Vigna unguiculata (L.) walp.] grown in California may receive little or no N fertilizer, or as much as 100 kg ha −1 N, usually applied preplant. Research was undertaken to determine whether N management could increase seed yield of furrow‐irrigated cowpeas on a fine‐loamy, mixed, thermic Haplic Durixeralf soil. Treatments included no N fertilizer, 168 kg ha −1 N as ammonium nitrate broadcast preplant, and side‐dressing with two N sources [calcium nitrate or urea‐ammonium nitrate (UAN) solutions] at two rates (56 or 168 kg ha −1 N) applied either at bloom or during podfill. Nitrogen application increased seed yield, with side‐dress application being more effective than preplant fertilization. Side‐dress application at bloom increased yield relative to application during podfill, and UAN produced higher yields than calcium nitrate. The higher rate of side‐dress N did not significantly increase seed yield. Preplant fertilization increased vegetative growth, but shoot dry matter differences disappeared during the reproductive period. Symbiotic N 2 fixation decreased and mineral N uptake increased (as indicated by ureide‐N and NO − 3 −N concentrations in xylem exudate, respectively) in response to N fertilization. Differences between preplant‐fertilized and control plants for these parameters did not persist through reproductive growth, whereas side‐dress application did cause differences during podfill. The increase in seed yield due to N management did not appear to be explained by increased growth, N accumulation in plant parts, or N supply during podfill. We propose that seed yield increased due to decreased consumption of photosynthates by nodules following inactivation of N 2 fixation by N fertilization.
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Claims 13
Claim · model-written summary
Nitrogen application increased cowpea seed yield.
- Taxon
- Cowpea
Vigna unguiculatat0 - Treatment
- Nitrogen applicatione0
- Outcome
- seed yielde0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen application increased seed yield”
t0“Cowpea”
Claim · model-written summary
Side dressing increased seed yield more than preplant fertilization.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- side‐dress applicatione0
- Outcome
- more effectivee0
- Direction
- more effectivee0
- Comparator
- preplant fertilizatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“side‐dress application being more effective than preplant fertilization”
t0“Cowpea”
Claim · model-written summary
Side dressing at bloom increased yield compared with podfill application.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Side‐dress application at bloome0
- Outcome
- yielde0
- Direction
- increasede0
- Comparator
- application during podfille0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Side‐dress application at bloom increased yield relative to application during podfill”
t0“Cowpea”
Claim · model-written summary
UAN produced higher cowpea yields than calcium nitrate.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- UANe0
- Outcome
- yieldse0
- Direction
- highere0
- Comparator
- calcium nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“UAN produced higher yields than calcium nitrate”
t0“Cowpea”
Claim · model-written summary
The higher side dress nitrogen rate did not significantly increase seed yield.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- higher rate of side‐dress Ne0
- Outcome
- seed yielde0
- Direction
- did not significantly increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The higher rate of side‐dress N did not significantly increase seed yield”
t0“Cowpea”
Claim · model-written summary
Preplant fertilization increased vegetative growth.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- Preplant fertilizatione0
- Outcome
- vegetative growthe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Preplant fertilization increased vegetative growth”
t0“Cowpea”
Claim · model-written summary
Shoot dry matter differences disappeared during the reproductive period.
- Taxon
- CowpeaVigna unguiculatat0
- Outcome
- shoot dry matter differencese0
- Direction
- disappearede0
- Qualifier
- during the reproductive periode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shoot dry matter differences disappeared during the reproductive period”
t0“Cowpea”
Claim · model-written summary
Nitrogen fertilization decreased symbiotic N2 fixation.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- N fertilizatione0
- Outcome
- Symbiotic N 2 fixatione0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Symbiotic N 2 fixation decreased and mineral N uptake increased (as indicated by ureide‐N and NO − 3 −N concentrations in xylem exudate, respectively) in response to N fertilization”
t0“Cowpea”
Claim · model-written summary
Nitrogen fertilization increased mineral nitrogen uptake.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- N fertilizatione0
- Outcome
- mineral N uptakee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Symbiotic N 2 fixation decreased and mineral N uptake increased (as indicated by ureide‐N and NO − 3 −N concentrations in xylem exudate, respectively) in response to N fertilization”
t0“Cowpea”
Claim · model-written summary
Differences in nitrogen parameters between preplant fertilized and control cowpeas did not persist through reproductive growth.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- preplant‐fertilizede0
- Outcome
- these parameterse0
- Direction
- did not persiste0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Differences between preplant‐fertilized and control plants for these parameters did not persist through reproductive growth”
t0“Cowpea”
Claim · model-written summary
Side dressing did cause nitrogen parameter differences during podfill.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- side‐dress applicatione0
- Outcome
- differences during podfille0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“side‐dress application did cause differences during podfill”
t0“Cowpea”
Claim · model-written summary
Seed yield gains did not appear explained by increased growth, nitrogen accumulation, or nitrogen supply during podfill.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- N managemente0
- Outcome
- increase in seed yielde0
- Qualifier
- did not appear to be explained by increased growth, N accumulation in plant parts, or N supply during podfille0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The increase in seed yield due to N management did not appear to be explained by increased growth, N accumulation in plant parts, or N supply during podfill”
t0“Cowpea”
Claim · model-written summary
Authors propose yield increased because nitrogen fertilization inactivated fixation and reduced photosynthate consumption by nodules.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- N fertilizatione0
- Outcome
- seed yield increasede0
- Qualifier
- decreased consumption of photosynthates by nodulese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We propose that seed yield increased due to decreased consumption of photosynthates by nodules following inactivation of N 2 fixation by N fertilization”
t0“Cowpea”
The same questions in other papers
nitrogen · yield · Vigna unguiculata (cowpea)Results differ
61 papers in the same direction as this paper · 6 in the opposite direction
- no effect
- negative
- no effect
64 papers more in this group
See all 68 papers →fertilization · growth · Vigna unguiculata (cowpea)Positive and negative results
130 papers in the same direction as this paper · 10 in the opposite direction · 2 reporting no difference from an alternative
- no effect
- no effect
- no effect
139 papers more in this group
See all 143 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.