Skip to main content
Kent Academic Repository

Field experimentation on rough land: the method of Papadakis reconsidered

Pearce, S.C. (1998) Field experimentation on rough land: the method of Papadakis reconsidered. Journal of Agricultural Science, 131 . pp. 1-11. ISSN 0021-8596. (doi:10.1017/s0021859698005486) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided) (KAR id:17487)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided.
Official URL:
https://doi.org/10.1017/s0021859698005486

Abstract

Much of the error in held experiments comes from environmental differences, which traditional methods (e.g. blocks or rows and columns) sometimes fail to control, especially if the fertility pattern is complex or unexpected. In 1937 Papadakis proposed an alternative approach in which the performance of each plot was judged by that of its neighbours. If a plot was situated in an area of generally high cropping, its own high crop was partly discounted but if surrounding plots were yielding poorly, it was given special weight. Adjustment was by the analysis of covariance. The method has not been much used, partly because it still lacks a mathematical basis and partly because it is suspected of bias in the estimation of contrasts between treatments. It has been studied here by simulation, i.e. bodies of data have been generated on the computer with known characteristics and then analysed by Papadakis's method to see if a correct answer was returned. Also, an improvement in the covariate is suggested and an iterative procedure developed to ensure more consistent results. It emerges that the suspicion of bias was unjustified. Also, the method can be extremely effective in reducing experimental error. In all its variant forms it has difficulty with outside plots, and for that reason is more effective on compact areas than on strips. Also, interference between plots is especially serious, because the neighbours affected are those needed to form the adjusting covariate. Discontinuities arising from past use of the land can cause problems but a method is suggested for minimizing their effect.

Item Type: Article
DOI/Identification number: 10.1017/s0021859698005486
Additional information: Part: Part 1
Subjects: S Agriculture
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Mathematics, Statistics and Actuarial Science
Depositing User: M.A. Ziai
Date Deposited: 29 Jun 2011 08:16 UTC
Last Modified: 09 Mar 2023 11:31 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/17487 (The current URI for this page, for reference purposes)

University of Kent Author Information

  • Depositors only (login required):

Total unique views for this document in KAR since July 2020. For more details click on the image.