Uniformity trials of tea

Usage

data("laycock.tea.uniformity")

Format

A data frame with 54 observations on the following 4 variables.

loc: location, L1 or L2
row: row
col: column
yield: yield (pounds)

Details

Actual physical dimensions for the tea shrubs are not given, so we use an estimate of four feet square for each shrub (which is similar to the eden.tea.uniformity experiment).

Location 1 (Laycock, page 108) is at the Research Station, Nyasaland. Plots were 10 by 15 bushes, harvested 23 times in 1942.

Field length: 8 plots * 10 bushes * 4 feet = 320 feet.

Field width: 4 plots * 15 bushes * 4 feet = 240 feet.

Location 2 (Laycock page 110) is at Mianga Estate, Nyasaland. Plots were 9 by 11 bushes, harvested 18 times in 1951/52.

Field length: 9 plots * 9 bushes * 4 feet = 324 feet.

Field width: 6 plots * 11 bushes * 4 feet = 264 feet.

Source

Laycock, D. H. (1955). The effect of plot shape in reducing the errors of tea experiments. Tropical Agriculture, 32, 107-114.

References

Zimmerman, Dale L., and David A. Harville. (1991). A random field approach to the analysis of field-plot experiments and other spatial experiments. Biometrics, 47, 223-239.

Examples

if (FALSE) { # \dontrun{

library(agridat)

data(laycock.tea.uniformity)
dat <- laycock.tea.uniformity

libs(desplot)
desplot(dat, yield ~ col*row|loc,
        flip=TRUE, aspect=322/252, # average of 2 locs
        main="laycock.tea.uniformity")

} # }