Uniformity trial of maize in South Africa

Usage

data("saunders.maize.uniformity")

Format

A data frame with 2500 observations on the following 4 variables.

row: row ordinate
col: column ordinate
yield: yield per plot, pounds
year: year

Details

These two maize uniformity trials were conducted by Potchefstroom Experiment Station, South Africa.

Each harvested unit was a plot of 10 plants, planted 3 feet by 3 feet in individual hills.

Dataset for 1928-1929 experiment

Rows 41-43 are missing.

Field width: 4 plots * 10 yards = 40 yards

Field length : 250 plots * 1 yard = 250 yards

Dataset for 1929-30 experiment

Row 255 is missing

There is an obvious edge effect in the first column.

Field width: 5 plots * 20 yards = 100 yards

Field length: 300 plots * 1 yard = 300 yards

Two possible outliers in the 1929-30 data were verified as being correctly transcribed from the source document.

This data was made available with special help from the staff at Rothamsted Research Library.

Rothamsted library scanned the paper documents to pdf. Screen captures of the pdf were saved as jpg files, then uploaded to an OCR conversion site. The resulting text was about 95 percent accurate and was carefully hand-checked and formatted into csv files.

Source

Rothamsted Research Library, Box STATS17 WG Cochran, Folder 5.

References

Rayner & A. R. Saunders. Statistical Methods, with Special Reference to Field Experiments.

Examples

if (FALSE) { # \dontrun{

  library(agridat)
  data(saunders.maize.uniformity)
  dat <- saunders.maize.uniformity

  libs(desplot)

  desplot(dat, yield ~ col*row, subset=year==1929,
          flip=TRUE, aspect=250/40,
          main="saunders.maize.uniformity 1928-29")
  desplot(dat, yield ~ col*row, subset=year==1930,
          flip=TRUE, aspect=300/100,
          main="saunders.maize.uniformity 1929-30")

} # }