Uniformity trial of corn at 3 locations in Iowa.

Usage

data("bryan.corn.uniformity")

Format

A data frame with 1728 observations on the following 4 variables.

expt: experiment (variety/orientation)
row: row
col: column
yield: yield, pounds per plot

Details

Three varieties of corn were planted. Each experiment was 48 rows, each row 48 hills long, .65 acres. A "hill" is a single hole with possibly multiple seeds. Spacing between the hills would be sqrt(43560 sq ft * .64) / 48 = 3.5 feet.

In the experiment code, K=Krug, I=Iodent, M=McCulloch (varieties of corn), 23=1923, 25=1925, E=East/West, N=North/South.

Each experiment was aggregated into experimental units by combining 8 hills, both in East/West direction and also in North/South direction. Thus, each field is represented twice in the data, once with "E" in the field name and once with "N".

Source

Arthur Bryan (1933). Factors Affecting Experimental Error in Field Plot Tests With Corn. Agricultural Experiment Station, Iowa State College. Tables 22-27. https://hdl.handle.net/2027/uiug.30112019568168

References

None

Examples

if (FALSE) { # \dontrun{
  library(agridat)
  data(bryan.corn.uniformity)
  dat <- bryan.corn.uniformity
  
  libs(desplot)
  desplot(dat, yield ~ col*row|expt,
          main="bryan.corn.uniformity",
          aspect=(48*3.5/(6*8*3.5)), # true aspect
          flip=TRUE, tick=TRUE)

  # CVs in Table 5, column 8 hills
  # libs(dplyr)
  # dat 
  #   summarize(cv=sd(yield)/mean(yield)*100)
  ##   expt    cv
  ## 1 K23E  10.9
  ## 2 K23N  10.9
  ## 3 I25E  16.3
  ## 4 I25N  17.0
  ## 5 M25E  16.2
  ## 6 M25N  17.2

} # }