Abstract
The high degradability of grass protein is an important factor in the low nitrogen (N) utilization of grazing bovines in intensive European grassland systems. We tested the hypothesis that protein degradability as measured by the Cornell Net Carbohydrate and Protein System (CNCPS) protein fractionation scheme, can be manipulated by herbage management tools, with the aim to reduce N loss to the environment. A field experiment comprising the factorial combinations of three fertilizer N application rates (0, 90 and 390 kg N ha−1 year−1), three regrowth periods (2–3, 4–5, and 6–7 weeks), two perennial ryegrass (Lolium perenne L.) cultivars [Aberdart (high sugar content) and Respect (low sugar content)] and two cutting heights (approximately 8 and 12 cm) was conducted at Teagasc, Johnstown Castle Research Centre, Wexford, Ireland. The plots were sampled during four seasons [September/October 2002 (late season), April 2003 (early season), May/June 2003 (mid season) and September 2003 (late season)] and protein fractions were determined in both sheath and lamina material. The protein was highly soluble and on average 19% and 28% of total N was in the form of non-protein N, 16% and 19% in the form of buffer-soluble protein, 52% and 40% in the form of buffer-insoluble protein, and 12% and 13% in the form of potentially available cell wall N for lamina and sheath material, respectively. In both materials only 0.9% of total N was present as unavailable cell wall N. In general the herbage management tools investigated did not have much effect on protein fractionation. The effects of regrowth period, cultivar and cutting height were small and inconsistent. High N application rates significantly increased protein degradability, especially during late season. This is relevant, as it has been shown that enhanced protein degradation increases the potential N loss through urine excretion at a time when urine-N excreted onto pasture is prone to leaching. However, the effect was most evident for sheath material, which forms only a small proportion of the animals' intake. It was concluded that there appears to be little scope for manipulating the herbage-N fractionation through herbage management. The consequences for modelling herbage quality could be positive as there does not seem to be a need to model the individual N fractions; in most cases the N fractions can be expressed as a fixed proportion of total N instead.
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Claims 9
Claim · model-written summary
Herbage management tools had little effect on protein fractionation of perennial ryegrass.
- Taxon
- Lolium perenne
Lolium perennee0 - Treatment
- herbage management toolse1
- Outcome
- protein fractionatione1
- Direction
- no_changeinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e1“In general the herbage management tools investigated did not have much effect on protein fractionation”
Claim · model-written summary
Regrowth period, cultivar and cutting height had small and inconsistent effects on protein fractionation.
- Taxon
- Lolium perenneLolium perennee0
- Treatment
- regrowth period, cultivar and cutting heighte2
- Outcome
- protein fractionatione1
- Direction
- no_changeinferrede2
- Qualifier
- small and inconsistente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e1“In general the herbage management tools investigated did not have much effect on protein fractionation”
e2“The effects of regrowth period, cultivar and cutting height were small and inconsistent”
Claim · model-written summary
High N application rates significantly increased protein degradability, especially in late season.
- Taxon
- Lolium perenneLolium perennee0
- Treatment
- High N application ratese3
- Outcome
- protein degradabilitye3
- Direction
- increasede3
- Setting
- late seasone3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e3“High N application rates significantly increased protein degradability, especially during late season”
Claim · model-written summary
The N effect on protein degradability was most evident in sheath material.
- Taxon
- Lolium perenneLolium perennee0
- Organ / stage
- sheath materiale4
- Treatment
- High N application ratese3
- Outcome
- protein degradabilitye3
- Direction
- higherinferrede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e3“High N application rates significantly increased protein degradability, especially during late season”
e4“However, the effect was most evident for sheath material, which forms only a small proportion of the animals' intake”
Claim · model-written summary
Non-protein N was on average 19% and 28% of total N in lamina and sheath material.
- Taxon
- Lolium perenneLolium perennee0
- Organ / stage
- lamina and sheath materiale5
- Outcome
- non-protein Ne5
- Value
- 19% and 28%e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e5“The protein was highly soluble and on average 19% and 28% of total N was in the form of non-protein N, 16% and 19% in the form of buffer-soluble protein, 52% and 40% in the form of buffer-insoluble protein, and 12% and 13% in the form of potentially available cell wall N for lamina and sheath material, respectively”
Claim · model-written summary
Buffer-soluble protein was 16% and 19% of total N in lamina and sheath material.
- Taxon
- Lolium perenneLolium perennee0
- Organ / stage
- lamina and sheath materiale5
- Outcome
- buffer-soluble proteine5
- Value
- 16% and 19%e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e5“The protein was highly soluble and on average 19% and 28% of total N was in the form of non-protein N, 16% and 19% in the form of buffer-soluble protein, 52% and 40% in the form of buffer-insoluble protein, and 12% and 13% in the form of potentially available cell wall N for lamina and sheath material, respectively”
Claim · model-written summary
Buffer-insoluble protein was 52% and 40% of total N in lamina and sheath material.
- Taxon
- Lolium perenneLolium perennee0
- Organ / stage
- lamina and sheath materiale5
- Outcome
- buffer-insoluble proteine5
- Value
- 52% and 40%e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e5“The protein was highly soluble and on average 19% and 28% of total N was in the form of non-protein N, 16% and 19% in the form of buffer-soluble protein, 52% and 40% in the form of buffer-insoluble protein, and 12% and 13% in the form of potentially available cell wall N for lamina and sheath material, respectively”
Claim · model-written summary
Potentially available cell wall N was 12% and 13% of total N in lamina and sheath material.
- Taxon
- Lolium perenneLolium perennee0
- Organ / stage
- lamina and sheath materiale5
- Outcome
- potentially available cell wall Ne5
- Value
- 12% and 13%e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e5“The protein was highly soluble and on average 19% and 28% of total N was in the form of non-protein N, 16% and 19% in the form of buffer-soluble protein, 52% and 40% in the form of buffer-insoluble protein, and 12% and 13% in the form of potentially available cell wall N for lamina and sheath material, respectively”
Claim · model-written summary
Unavailable cell wall N was 0.9% of total N in both materials.
- Taxon
- Lolium perenneLolium perennee0
- Organ / stage
- both materialse6
- Outcome
- unavailable cell wall Ne6
- Value
- 0.9%e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“two perennial ryegrass (Lolium perenne L.) cultivars”
e6“In both materials only 0.9% of total N was present as unavailable cell wall N”
The same questions in other papers
pruning · quality: protein · Lolium perenne (perennial ryegrass)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
nitrogen · quality: protein · Lolium perenne (perennial ryegrass)Results agree
2 papers in the same direction as this paper
- no effect
- no effect
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.