williams.cotton.uniformity {agridat} | R Documentation

## Uniformity trial of cotton

### Description

Uniformity trial of cotton at Narrabri, New South Wales, 1984.

### Format

A data frame with 288 observations on the following 3 variables.

`row`

  row

`col`

  column

`yield`

  lint yield, kg/ha divided by 10

### Details

Cotton uniformity trial grown at Narrabri, New South Wales, 1984-1985. Plots were 12m long, 1m apart, 12 rows by 24 columns, with an irrigation furrow between columns.

Field width: 24 plots * 1 m = 24 m

Field length: 12 plots * 12 m = 144 m

### Source

Williams, ER and Luckett, DJ. 1988. The use of uniformity data in the design and analysis of cotton and barley variety trials. Australian Journal of Agricultural Research, 39, 339-350. http://doi.org/10.1071/AR9880339

### Examples

    data(williams.cotton.uniformity)
    dat <- williams.cotton.uniformity

    if(require(desplot)){
    desplot(yield ~ col*row, dat,
            aspect=144/24, # true aspect
            main="williams.cotton.uniformity")
    }

    # Smoothed contour/persp plot like Williams 1988 Fig 1a, 2a
    dat$fit <- fitted(loess(yield~col*row, dat, span=.5))
    require("lattice")
    contourplot(fit~col*row, data=dat,
                aspect=144/24,
                region=TRUE, cuts=6, col.regions=RedGrayBlue,
                main="williams.cotton.uniformity")
    # wireframe(fit~col*row, data=dat, zlim=c(100, 250),
    #           main="williams.cotton.uniformity")

    # Williams table 1
    anova(aov(yield ~ factor(row) + factor(col), dat))

[Package agridat version 1.16 Index]