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A predictive model of seasonal changes in herbage digestibility

Published online by Cambridge University Press:  27 March 2009

A. W. Illius
A. W. Illius
Affiliation:
School of Agriculture, University of Edinburgh, West Mains Road, Edinburgh, EH9 ZJO
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Summary

A quantitative description of the factors underlying seasonal changes in herbage digestibility is developed and applied to sets of data from S. 24 and S. 23 perennial ryegrass. A new variable, relative maturity, is used to describe the effect of defoliation in interrupting the process of tiller maturation which leads to the decline in digestibility. For S. 24, the model explained 95·5% of variation in digestibility decline, R.S.D. = 1·07, allowing accurate prediction of digestibility. For S. 23, 87·5% of variation was explained, R.S.D. = 1·85. The model for S. 24 also worked well on data from a different site, nitrogen level and cutting regime, and the question of the model's generality is discussed. Relative maturity appears to be a useful concept in describing the physiological maturity of swards under different harvesting regimes.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 105 , Issue 3 , December 1985 , pp. 505 - 512
Copyright
Copyright © Cambridge University Press 1985

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References

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