agridat (version 1.16)

baker.barley.uniformity: Uniformity trials of barley, 10 years on same ground

Description

Uniformity trials of barley at Davis, California, 1925-1935, 10 years on same ground.

Arguments

Format

A data frame with 570 observations on the following 4 variables.

row

row

col

column

year

year

yield

yield, pounds/acre

Details

Ten years of uniformity trials were sown on the same ground. Baker (1952) shows a map of the field, which gravel subsoil extended from the upper right corner diagonally lower-left. This results in lower yields as seen on the 10-year average map.

Field width: 19 plots = 827 ft

Field length: 3 plots * 161 ft + 2 alleys * 15 feet = 513 ft

Examples

Run this code
# NOT RUN {
data(baker.barley.uniformity)
dat <- baker.barley.uniformity

# Ten-year average
dat2 <- aggregate(yield ~ row*col, data=dat, FUN=mean, na.rm=TRUE)

if(require(desplot)){
  desplot(yield~col*row|year, data=dat,
          aspect = 513/827, # true aspect
          main="baker.barley.uniformity - heatmaps by year")
}
if(require(desplot)){
  desplot(yield~col*row, data=dat2,
          aspect = 513/827, # true aspect
          main="baker.barley.uniformity - heatmap of 10-year average")
  # Note low yield in upper right, slanting to left a bit due to sandy soil
  # as shown in Baker figure 1.
}

# Baker fig 2, stdev vs mean
dat3 <- aggregate(yield ~ row*col, data=dat, FUN=sd, na.rm=TRUE)
plot(dat2$yield, dat3$yield, xlab="Mean yield", ylab="Std Dev yield",
     main="baker.barley.uniformity")

# Baker table 4, correlation of plots across years
if(require(reshape2)){
mat <- acast(dat, row+col~year)
round(cor(mat, use='pair'),2)
}

# }

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