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Confidence Intervals for Staple and Effective LER Values

Published online by Cambridge University Press:  03 October 2008

B. A. Oyejola
Affiliation:
Department of Statistics, University of Ilorin, PMB 1515, Ilorin, Nigeria

Summary

When an intercrop fails to produce a required proportion of the sole crop yield, but produces a yield advantage over the sole crop, the method of sole crop supplementation has been suggested by many authors including Mead and Willey (1980) and Riley (1985). Modifications to the Land Equivalent Ratio (LER), used for assessing yield advantages, have been suggested and referred to as staple LERs (SLERs) and Effective LERs (ELERs). In this paper, a graphical method of estimating the SLER and ELER values (and consequently their yield advantages) is presented. The graphical estimation of the confidence interval for the SLER and ELER values is also shown.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1990

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References

REFERENCES

Mead, R. & Willey, R. W. (1980). The concept of a Land Equivalent Ratio and advantages in yields from intercropping. Experimental Agriculture 16:217228.CrossRefGoogle Scholar
Oyejola, B. A. (1983). Some Statistical Considerations in the Use of Land Equivalent Ratio to Assess Yield Advantages in Intercropping. PhD thesis, University of Reading.Google Scholar
Pearce, S. C. & Gilliver, B. (1979). Graphical assessment of intercropping methods. Journal of Agricultural Science, Cambridge 93:5158.Google Scholar
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Willey, R. W. (1985). Evaluation and presentation of intercropping advantages. Experimental Agriculture 21:119133.CrossRefGoogle Scholar