Abstract
Abstract Four cultivars of perennial ryegrass (intermediate diploid cv. Talbot and tetraploid cv. Barlatra, and late diploid cv. Parcour and tetraploid cv. Petra) were each sown at 10,20 and 30 kg ha ‐1 , all with 3 kg ha ‐1 of white clover cv. Donna. Herbage productivity was measured over 3 harvest years, 1982–84. under two annual rates of fertilizer N (0 and 150 kg ha ‐1 ); the 150 kg ha ‐1 rate was split equally between March and August applications. Fertilizer N increased total herbage DM production; the 3‐year means for the 0 and 150 kg ha ‐1 N rates were 8·04 and 8·91 t ha ‐1 , respectively. In successive years, total herbage responses to N (kg DM (kg N applied) ‐1 ) were 6·6, 35 and 72 (overall mean, 58). Mean white clover DM production over the 3 years was reduced from 4·48 t ha ‐1 at nil N to 2·82 t ha ‐1 at the 150 kg ha ‐1 rate, a fall of 37%. Grass seed rate did not influence total herbage production or white clover performance. The two intermediate perennial ryegrass cultivars had a marginal advantage in total herbage production over the two late cultivars, but white clover content and production were higher with tetraploids than diploids. It is concluded that the value of increased herbage production from strategic use of fertilizer N has to be weighed against its depressive effect on white clover performance; application of 75 kg ha ha ‐1 N in both spring and autumn was excessively high if maintenance of a good white clover content in the sward is an objective. There is considerable flexibility in the grass: clover seed ratio in seeds mixtures. Modern highly‐productive perennial ryegrass varieties do not differ substantially in compatibility with white clover but tetraploids permit better clover performance than diploids.
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Claims 9
Claim · model-written summary
Fertilizer nitrogen increased total herbage dry matter production from 8·04 to 8·91 t ha ‐1.
- Taxon
- perennial ryegrass
Lolium perennet0 - Treatment
- 150 kg ha ‐1 Ne0
- Outcome
- total herbage DM productione0
- Direction
- increasede0
- Value
- 8·91 t ha ‐1e0
- Comparator
- 0e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilizer N increased total herbage DM production; the 3‐year means for the 0 and 150 kg ha ‐1 N rates were 8·04 and 8·91 t ha ‐1 , respectively.”
t0“perennial ryegrass”
Claim · model-written summary
Herbage responses to N were 6·6, 35 and 72 in successive years.
- Taxon
- perennial ryegrassLolium perennet0
- Outcome
- total herbage responses to Ne0
- Value
- 6·6, 35 and 72e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In successive years, total herbage responses to N (kg DM (kg N applied) ‐1 ) were 6·6, 35 and 72 (overall mean, 58).”
t0“perennial ryegrass”
Claim · model-written summary
Overall mean herbage response to N was 58.
- Taxon
- perennial ryegrassLolium perennet0
- Outcome
- overall meane0
- Value
- 58e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“overall mean, 58”
t0“perennial ryegrass”
Claim · model-written summary
Nitrogen reduced mean white clover dry matter production by 37%, from 4·48 to 2·82 t ha ‐1.
- Taxon
- white clover
Trifolium repense0 - Treatment
- 150 kg ha ‐1e0
- Outcome
- white clover DM productione0
- Direction
- reducede0
- Value
- 37%e0
- Qualifier
- 4·48 t ha ‐1e0
- Comparator
- nil Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Mean white clover DM production over the 3 years was reduced from 4·48 t ha ‐1 at nil N to 2·82 t ha ‐1 at the 150 kg ha ‐1 rate, a fall of 37%.”
Claim · model-written summary
Grass seed rate did not influence total herbage production or white clover performance.
- Taxon
- white cloverTrifolium repense0
- Treatment
- Grass seed ratee0
- Outcome
- total herbage production or white clover performancee0
- Direction
- did not influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Grass seed rate did not influence total herbage production or white clover performance.”
Claim · model-written summary
Intermediate perennial ryegrass cultivars had a marginal advantage in total herbage production over late cultivars.
- Taxon
- perennial ryegrassLolium perennee0
- Material
- intermediate perennial ryegrass cultivarse0
- Outcome
- total herbage productione0
- Direction
- marginal advantagee0
- Comparator
- late cultivarse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The two intermediate perennial ryegrass cultivars had a marginal advantage in total herbage production over the two late cultivars”
Claim · model-written summary
White clover content and production were higher with tetraploid than diploid ryegrass.
- Taxon
- white cloverTrifolium repense0
- Material
- tetraploidse0
- Outcome
- white clover content and productione0
- Direction
- highere0
- Comparator
- diploidse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“white clover content and production were higher with tetraploids than diploids.”
Claim · model-written summary
The authors judged 75 kg ha ha ‐1 N in spring and autumn excessively high for maintaining good white clover content.
- Taxon
- white cloverTrifolium repense0
- Outcome
- application of 75 kg ha ha ‐1 N in both spring and autumn was excessively highe0
- Qualifier
- maintenance of a good white clover contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“application of 75 kg ha ha ‐1 N in both spring and autumn was excessively high if maintenance of a good white clover content in the sward is an objective.”
Claim · model-written summary
The authors concluded that grass to clover seed ratio is flexible in seed mixtures.
- Outcome
- considerable flexibility in the grass: clover seed ratioe0
TrifoliumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There is considerable flexibility in the grass: clover seed ratio in seeds mixtures.”
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density · yield · Trifolium repens (white clover)Positive and negative results
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See all 10 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.