Uniformity trial of cotton

Uniformity trial of cotton in Greece, 1938

Usage

data("christidis.cotton.uniformity")

Format

A data frame with 1024 observations on the following 4 variables.

col

column

row

row

yield

yield, kg/unit

block

block factor

Details

The experiment was conducted in 1938 at Sindos by the Greek Cotton Research Institute.

Each block consisted of 20 rows, 1 meter apart and 66 meters long. Two rows on each side and 1 meter on each end were removed for borders. Each row was divided into 4 meter-lengths and harvested separately. There were 4 blocks, oriented at 0, 30, 60, 90 degrees.

Each block contained 16 rows, each 64 meters long.

Field width: 16 units * 4 m = 64 m

Field depth: 16 rows * 1 m = 16 m

Source

Christidis, B. G. (1939). Variability of Plots of Various Shapes as Affected by Plot Orientation. Empire Journal of Experimental Agriculture 7: 330-342. Table 1.

References

None

Examples

if (FALSE) { # \dontrun{

library(agridat)
data(christidis.cotton.uniformity)
dat <- christidis.cotton.uniformity
  
# Match the mean yields in table 2. Not sure why '16' is needed
# sapply(split(dat$yield, dat$block), mean)*16
  
libs(desplot)
dat$yld <- dat$yield/4*1000 # re-scale to match Christidis fig 1
desplot(dat, yld ~ col*row|block,
        flip=TRUE, aspect=(16)/(64),
        main="christidis.cotton.uniformity")

} # }