Abstract
A field study was made of the tiller dynamics of the New Zealand perennial ryegrass ( Lolium perenne L.) cultivars Grasslands Ruanui, selected from a Hawke's Bay ecotype, and Ellett, selected from the Mangere ecotype. The work tested whether nitrogen (N) fertiliser or irrigation (Irr) could manipulate the persistence strategies of these morphologically distinct perennial ryegrass ecotypes, represented by these cultivars. Tiller births and deaths, and tiller survival, were monitored over 2 years, under rotational grazing by dairy cows. Patterns of cultivar tiller birth and death were similar. Much of the temporal change in tiller population density was shown to be a response to increasing or decreasing herbage mass associated with seasonal feed surplus or deficit. The probability of tiller survival between observation dates varied markedly with date, and was lowest in autumn. The cultivar effect on tiller survival was small but a significant ( P < 0.05) cultivar × date interaction was detected, with survival probability for Ellett tending to be higher than for Grasslands Ruanui in March–April 1997 but lower from July 1997 until March 1998. A cohort effect on tiller survival was also identified, in that tillers formed in January, July, and August 1997 had lower survival probability than those formed at other times. N-treated plots produced 34% more tillers than did untreated plots, and irrigation had no effect on overall tiller density. N and Irr treatments had variable effects on tiller survival. Size density compensation theory and analysis of survival probability are introduced to aid the interpretation of tiller dynamics data.
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Claims 8
Claim · model-written summary
N-treated plots produced 34% more tillers than untreated plots.
- Taxon
- perennial ryegrass
Lolium perennet0 - Treatment
- N-treated plotse0
- Outcome
- tillerse0
- Direction
- moree0
- Value
- 34%e0
- Comparator
- untreated plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“N-treated plots produced 34% more tillers than did untreated plots”
Claim · model-written summary
Irrigation had no effect on overall tiller density.
- Taxon
- perennial ryegrassLolium perennet0
- Treatment
- irrigatione0
- Outcome
- overall tiller densitye0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“irrigation had no effect on overall tiller density”
Claim · model-written summary
N and irrigation treatments had variable effects on tiller survival.
- Taxon
- perennial ryegrassLolium perennet0
- Treatment
- N and Irr treatmentse0
- Outcome
- tiller survivale0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“N and Irr treatments had variable effects on tiller survival”
Claim · model-written summary
Tiller survival probability varied markedly with date and was lowest in autumn.
- Taxon
- perennial ryegrassLolium perennet0
- Outcome
- probability of tiller survivale0
- Direction
- loweste0
- Qualifier
- autumne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“The probability of tiller survival between observation dates varied markedly with date, and was lowest in autumn”
Claim · model-written summary
A significant cultivar x date interaction: Ellett survival tended to be higher than Grasslands Ruanui in March-April 1997 but lower from July 1997 to March 1998.
- Taxon
- perennial ryegrassLolium perennet0
- Material
- Ellette0
- Outcome
- survival probabilitye0
- Comparator
- Grasslands Ruanuie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“a significant ( P < 0.05) cultivar × date interaction was detected, with survival probability for Ellett tending to be higher than for Grasslands Ruanui in March–April 1997 but lower from July 1997 until March 1998”
Claim · model-written summary
Tillers formed in January, July and August 1997 had lower survival probability than those formed at other times.
- Taxon
- perennial ryegrassLolium perennet0
- Outcome
- survival probabilitye0
- Direction
- lowere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“tillers formed in January, July, and August 1997 had lower survival probability than those formed at other times”
Claim · model-written summary
Much of the temporal change in tiller population density was a response to changing herbage mass.
- Taxon
- perennial ryegrassLolium perennet0
- Outcome
- temporal change in tiller population densitye0
- Qualifier
- increasing or decreasing herbage masse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“Much of the temporal change in tiller population density was shown to be a response to increasing or decreasing herbage mass”
Claim · model-written summary
Patterns of tiller birth and death were similar between cultivars.
- Taxon
- perennial ryegrassLolium perennet0
- Outcome
- tiller birth and deathe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“perennial ryegrass cultivars”
e0“Patterns of cultivar tiller birth and death were similar”
The same questions in other papers
irrigation · yield · Lolium perenne (perennial ryegrass)Positive and negative results
6 in the opposite direction
- positive
- positive
- positive
3 papers more in this group
See all 7 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.