agridat (version 1.21)

piepho.barley.uniformity: Uniformity trial of barley

Description

Uniformity trial of barley in Germany

Usage

data("piepho.barley.uniformity")

Format

A data frame with 1080 observations on the following 5 variables.

row

row ordinate

col

column ordinate

yield

yield per plot

Details

Uniformity trial of barley at Ihinger Hof farm, conducted by the University of Hohenheim, Germany, in 2007.

Note: The paper by Piepho says "The trial had 30 rows and 36 columns. Plot widths were 1.90 m along rows and 3.73 m along columns." However, the SAS code supplement to the paper, called "PBR_1654_sm_example1.sas", has row=1-36, col=1-30. We cannot determine which dimension is "row" and which is "column", and therefore cannot determine the actual dimensions of the field.

References

None

Examples

if (FALSE) {
  data(piepho.barley.uniformity) 
  dat <- piepho.barley.uniformity
  libs(desplot)
  desplot(yield ~ col*row, dat,
          tick=TRUE, # aspect unknown
          main="piepho.barley.uniformity.csv")

  libs(asreml,dplyr)
  dat <- mutate(dat, x=factor(col), y=factor(row))
  dat <- arrange(dat, x, y)
  
  # Piepho AR1xAR1 model (in random term, NOT residual)
  m1 <- asreml(data=dat,
               yield ~ 1, 
               random = ~ x + y + ar1(x):ar1(y), 
               residual = ~  units,
               na.action=na.method(x="keep") )
  m1 <- update(m1)
  # Match Piepho table 3, footnote 4: .9671, .9705 for col,row correlation
  # Note these parameters are basically at the boundary of the parameter
  # space. Questionable fit.
  libs(lucid)
  lucid::vc(m1) 
}