Abstract
Lolium perenne L. (perennial ryegrass) exhibits poor persistence in subtropical environments and this is often characterised by weed invasion. The effect of applied nitrogen (N) (120-720 kg/ha.year), on weed invasion of perennial ryegrass was examined during the establishment year. Weed tiller densities ranged from 50 tillers/m2 (at 360 kg N/ha.year) during November 1993, to 2400 tillers/m2 (at 120 kg N/ha.year) during February 1994. Increasing levels of applied N up to 360 kg/ha.year reduced both weed tiller densities and relative frequencies in perennial ryegrass pastures. Seasonally, high weed tiller densities (up to 2400 tillers/m2 at 120 kg N/ha.year) and high frequencies (46-82% for 120 and 600 kg N/ha.year, respectively) were observed over midsummer (December) to autumn (May). Applying N at levels above 360 kg/ha.year (or 30 kg/ha.month) is useful in minimising weed invasion of perennial ryegrass during its establishment under subtropical conditions.
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Claims 7
Claim · model-written summary
Weed tiller density was 50 tillers/m2 at 360 kg N/ha.year in November 1993.
- Taxon
- Lolium perenne L. (perennial ryegrass)
Lolium perennee1 - Treatment
- 360 kg N/ha.yeare0
- Interactor
- Weede0
- Outcome
- Weed tiller densitiese0
- Value
- 50 tillers/m2e0
- Qualifier
- November 1993e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Weed tiller densities ranged from 50 tillers/m2 (at 360 kg N/ha.year) during November 1993”
e1“Lolium perenne L. (perennial ryegrass)”
Claim · model-written summary
Weed tiller density was 2400 tillers/m2 at 120 kg N/ha.year in February 1994.
- Taxon
- Lolium perenne L. (perennial ryegrass)Lolium perennee2
- Treatment
- 120 kg N/ha.yeare0
- Interactor
- Weede1
- Outcome
- Weed tiller densitiese1
- Value
- 2400 tillers/m2e0
- Qualifier
- February 1994e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2400 tillers/m2 (at 120 kg N/ha.year) during February 1994”
e1“Weed tiller densities ranged from 50 tillers/m2”
e2“Lolium perenne L. (perennial ryegrass)”
Claim · model-written summary
Increasing applied N to 360 kg/ha.year reduced weed tiller density.
- Taxon
- Lolium perenne L. (perennial ryegrass)Lolium perennee1
- Treatment
- Increasing levels of applied N up to 360 kg/ha.yeare0
- Interactor
- weede0
- Outcome
- weed tiller densitiese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing levels of applied N up to 360 kg/ha.year reduced both weed tiller densities and relative frequencies in perennial ryegrass pastures”
e1“Lolium perenne L. (perennial ryegrass)”
Claim · model-written summary
Increasing applied N to 360 kg/ha.year reduced weed relative frequency.
- Taxon
- Lolium perenne L. (perennial ryegrass)Lolium perennee1
- Treatment
- Increasing levels of applied N up to 360 kg/ha.yeare0
- Interactor
- weede0
- Outcome
- relative frequenciese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing levels of applied N up to 360 kg/ha.year reduced both weed tiller densities and relative frequencies in perennial ryegrass pastures”
e1“Lolium perenne L. (perennial ryegrass)”
Claim · model-written summary
Seasonal weed tiller density reached 2400 tillers/m2 at 120 kg N/ha.year from midsummer to autumn.
- Taxon
- Lolium perenne L. (perennial ryegrass)Lolium perennee2
- Treatment
- 120 kg N/ha.yeare0
- Interactor
- weede0
- Outcome
- weed tiller densitiese0
- Direction
- highe0
- Value
- 2400 tillers/m2e0
- Qualifier
- midsummer (December) to autumn (May)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high weed tiller densities (up to 2400 tillers/m2 at 120 kg N/ha.year)”
e1“over midsummer (December) to autumn (May)”
e2“Lolium perenne L. (perennial ryegrass)”
Claim · model-written summary
Seasonal weed frequencies ranged from 46% at 120 to 82% at 600 kg N/ha.year.
- Taxon
- Lolium perenne L. (perennial ryegrass)Lolium perennee1
- Interactor
- weede2
- Outcome
- frequenciese0
- Direction
- highe0
- Value
- 46-82%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high frequencies (46-82% for 120 and 600 kg N/ha.year, respectively)”
e1“Lolium perenne L. (perennial ryegrass)”
e2“Weed tiller densities ranged from 50 tillers/m2”
Claim · model-written summary
The authors recommend nitrogen above 360 kg/ha.year to minimize weed invasion during establishment.
- Taxon
- Lolium perenne L. (perennial ryegrass)Lolium perennee1
- Treatment
- N at levels above 360 kg/ha.yeare0
- Interactor
- weede0
- Outcome
- minimising weed invasione0
- Setting
- subtropical conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applying N at levels above 360 kg/ha.year (or 30 kg/ha.month) is useful in minimising weed invasion of perennial ryegrass during its establishment under subtropical conditions”
e1“Lolium perenne L. (perennial ryegrass)”
The same questions in other papers
nitrogen · weed · Lolium perenne (perennial ryegrass)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
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.