Abstract
Three studies were conducted to investigate effect of stubble defoliation by variegated cutworm, Peridroma saucia (Hübner), on establishment and dry-matter production of annual weeds in alfalfa. Weeds in 1982 were mostly foxtail grasses, Setaria spp., but weeds in 1983 were a mixture of grass and broadleaved species. Weed density, biomass, and percentage by weight at harvest increased linearly with increasingly severe stubble defoliation. Stubble defoliation also increased weed density, biomass, and percentage composition at carry-over harvest. Weed emergence was unaffected by severity of stubble defoliation. Consequently, differences in weed density at harvest were caused primarily by differential rates of weed mortality between defoliated (≤72.3%) and nondefoliated (94.2%) treatments. Alfalfa dry-matter production was not suppressed by presence of weeds during treated and carry-over cutting. Instead, weeds added to alfalfa by filling in gaps in the stand rather than by replacing alfalfa biomass. Competition by weeds, however, could be expected to reduce long-term stand vigor and to hasten alfalfa stand decline.
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Claims 7
Claim · model-written summary
Weed density, biomass and percentage by weight at harvest increased linearly with defoliation severity.
- Taxon
- alfalfa
Medicago sativat0 - Treatment
- stubble defoliatione0
- Interactor
- weede0weed
- Outcome
- Weed density, biomass, and percentage by weight at harveste0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alfalfa”
e0“Weed density, biomass, and percentage by weight at harvest increased linearly with increasingly severe stubble defoliation.”
Claim · model-written summary
Stubble defoliation increased weed density, biomass and percentage composition at carry-over harvest.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- stubble defoliatione0
- Interactor
- weede0weed
- Outcome
- weed density, biomass, and percentage composition at carry-over harveste0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alfalfa”
e0“Stubble defoliation also increased weed density, biomass, and percentage composition at carry-over harvest.”
Claim · model-written summary
Weed emergence was unaffected by defoliation severity.
- Taxon
- alfalfaMedicago sativat0
- Treatment
- stubble defoliatione0
- Interactor
- weede0weed
- Outcome
- Weed emergencee0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alfalfa”
e0“Weed emergence was unaffected by severity of stubble defoliation.”
Claim · model-written summary
Weed mortality was at most 72.3% with defoliation versus 94.2% without defoliation.
- Taxon
- AlfalfaMedicago sativat0
- Treatment
- defoliatede0
- Interactor
- weede0weed
- Outcome
- weed mortalitye0
- Value
- ≤72.3%e0
- Qualifier
- 94.2%e0
- Comparator
- nondefoliatede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Alfalfa”
e0“weed mortality between defoliated (≤72.3%) and nondefoliated (94.2%) treatments.”
Claim · model-written summary
Weeds did not suppress alfalfa dry matter production during treated and carry-over cutting.
- Taxon
- AlfalfaMedicago sativae0
- Interactor
- weedse0weed
- Outcome
- Alfalfa dry-matter productione0
- Direction
- not suppressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Alfalfa dry-matter production was not suppressed by presence of weeds during treated and carry-over cutting.”
Claim · model-written summary
Weeds filled gaps in the alfalfa stand rather than replacing alfalfa biomass.
- Taxon
- alfalfaMedicago sativae0
- Interactor
- weedse0weed
- Outcome
- filling in gaps in the stande0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“weeds added to alfalfa by filling in gaps in the stand rather than by replacing alfalfa biomass.”
Claim · model-written summary
The authors expect weed competition to reduce long-term stand vigor and hasten alfalfa decline.
- Taxon
- alfalfaMedicago sativae0
- Interactor
- weedse0weed
- Outcome
- long-term stand vigore0
- Direction
- reducee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Competition by weeds, however, could be expected to reduce long-term stand vigor and to hasten alfalfa stand decline.”
The same questions in other papers
pruning · weed · Medicago sativa (alfalfa)Positive and negative results
1 paper in the same direction as this paper · 4 in the opposite direction
- no effect
- negative
- negative
2 papers more in this group
See all 6 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.