Uniformity trials of barley, 10 years on same ground

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

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

Source

Baker, GA and Huberty, MR and Veihmeyer, FJ. (1952) A uniformity trial on unirrigated barley of ten years' duration. Agronomy Journal, 44, 267-270. https://doi.org/10.2134/agronj1952.00021962004400050011x

Examples

# \dontrun{

library(agridat)

data(baker.barley.uniformity)
dat <- baker.barley.uniformity

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

libs(desplot)
desplot(dat, yield~col*row|year,
        aspect = 513/827, # true aspect
        main="baker.barley.uniformity - heatmaps by year")

desplot(dat2, yield~col*row,
        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
# libs(reshape2)
# mat <- acast(dat, row+col~year)
# round(cor(mat, use='pair'),2)

# }