agridat (version 1.12)

stephens.sorghum.uniformity: Uniformity trial of sorghum silage

Description

Uniformity trial of sorghum silage, 100x20 plots.

Format

A data frame with 2000 observations on the following 3 variables.

row

row ordinate

col

column / rod ordinate

yield

yield, ounces

Details

Grown near Chillicothe, TX in 1915. Rows 40 inches apart. Each row harvested in 1-rod (16.5 ft) lengths. East side higher yielding than west side. Yields are weight (ounces) of green forage each rod-row. Total area harvested: 100*40/12 = 333.33 feet by 20*16.5=330 feet.

Examples

# NOT RUN {
data(stephens.sorghum.uniformity)
dat <- stephens.sorghum.uniformity

dat <- subset(dat, row>2 & row<99) # omit outer two rows
# mean(dat$yield) # 180.27
# range(dat$yield) # 75,302 matches Stephens

# densityplot(~dat$yield) # Stephens figure 3

# Aggregate 4 side-by-side rows.
# Similar to Stephens Figure 7.  North at top.  East at right.
d4 <- dat
d4$row2 <- ceiling((d4$row-2)/4)
d4 <- aggregate(yield ~ row2+col, data=d4, FUN=sum)
d4$row2 <- 25-d4$row2 # flip horizontally
desplot(yield ~ row2*col, data=d4, flip=TRUE, main="stephens.sorghum.uniformity",
        at=c(500,680,780,1000), col.regions=c('white','gray','gray30'))
# }