christidis.cotton.uniformity {agridat} | R Documentation

## Uniformity trial of cotton

### Description

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 borderr. 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

    ## Not run:

      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

      require(desplot)
      dat$yld <- dat$yield/4*1000 # re-scale to match Fig 1
      desplot(yld ~ col*row|block, data=dat,
              flip=TRUE, aspect=(16)/(64),
              main="christidis.cotton.uniformity")

    ## End(Not run)

[Package agridat version 1.16 Index]