Uniformity trial of cotton
Uniformity trial of cotton at Narrabri, New South Wales, 1984.
A data frame with 288 observations on the following 3 variables.
rowrow
colcolumn
yieldlint yield, kg/ha divided by 10
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
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. https://doi.org/10.1071/AR9880339
## Not run:
library(agridat)
data(williams.cotton.uniformity)
dat <- williams.cotton.uniformity
libs(desplot)
desplot(dat, yield ~ col*row,
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))
libs("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))
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