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| Web URL(s): | http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2494.1988.tb02136.x/epdf
Last checked: 10/02/2015
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| Publication Type:
| Refereed |
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| Author(s): | Parsons, A. J.;
Johnson, I. R.;
Williams, J. H. H. |
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| Author Affiliation: | Istitute for Animal and Grassland Production, Hurley, UK and University of New England, Armidale, Australia. |
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| Title: | Leaf Age Structure and Canopy Photosynthesis in Rotationally and Continuously Grazed Swards |
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| Source: | Grass and Forage Science. Vol. 43, No. 1, March 1988, p. 1-14. |
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| Publishing Information: | Oxford, Blackwell Scientific Publications |
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| Keywords: | TIC Keywords: Leaf age; Canopy; Photosynthesis; Lolium perenne
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| Abstract/Contents: | "The leaf age structure of ryegrass canopies and its role in canopy photosynthesis were compared under continuous and rotational grazing by sheep. Under continuous grazing, an increase in the intensity of grazing increased the proportion (by leaf area) of young leaves in the sward. A mechanistic mathematical model was used to demonstrate how this may have arisen, even though it would largely have been the young leaves that were eaten. However, the observations do not confirm the hypothesis that continuously grazed swards have a characteristically greater proportion of young leaves and so a greater photosynthetic potential, than rotationally grazed one. The proportion of young leaves increased during regrowth following severe rotational grazine (residual LAI < 0.5) and the photosynthetic potential of the canopy became greater than under continuous grazing. A model of canopy photosynthesis was used to demonstrate that the observed difference in the proportion of young leaves alone was unlikely to account for all the differences in canopy photosynthesis between managements, and further differences in canopy structure were evaluated. Dispite the delay in the restoration of leaf area following severe grazing in a rotation, the total photosynthetic uptake of a system involving some 12-13 days regrowth and 3 days grazing exceeded that of a well-utilized contiuously grazed sward. Regrowths of longer duration led to progressively greater total photosynthetic uptake, though this was not considered synonymous with greater yield." |
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| Language: | English |
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| References: | 46 |
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| Note: | Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Parsons, A. J., I. R. Johnson, and J. H. H. Williams. 1988. Leaf Age Structure and Canopy Photosynthesis in Rotationally and Continuously Grazed Swards. Grass Forage Sci. 43(1):p. 1-14. |
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| Web URL(s):
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2494.1988.tb02136.x/epdf
Last checked: 10/02/2015
Requires: PDF Reader
Access conditions: Item is within a limited-access website |
| 
MSU catalog number: SB 197 .B7 |
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