agridat (version 1.16)

day.wheat.uniformity: Uniformity trial of wheat

Description

Uniformity trial of wheat in 1903 in Missouri.

Usage

data("day.wheat.uniformity")

Format

A data frame with 3090 observations on the following 4 variables.

row

row

col

col

grain

grain weight, grams

straw

straw weight, grams

Details

These data are from the Shelbina field of the Missouri Agricultural Experiment Station. The field (plat) was about 1/4 acre in area and apparently uniform throughout. In the fall of 1912, wheat was drilled in rows 8 inches apart, each row 155 feet long. The wheat was harvested in June, in 5-foot segments. The gross weight and the grain weight was measured, the straw weight was calculated by subtraction.

Field width: 31 series * 5 feet = 155 feet

Field length: 100 rows, 8 inches apart = 66.66 feet

References

James W. Day (1920). The relation of size, shape, and number of replications of plats to probable error in field experimentation. Agronomy Journal, 12, 100-105. http://doi.org/10.2134/agronj1920.00021962001200030002x

Examples

# NOT RUN {
  
  data(day.wheat.uniformity)
  dat <- day.wheat.uniformity

  require(desplot)
  desplot(grain~col*row, data=dat,
          flip=TRUE, aspect=(100*8)/(155*12), # true aspect
          main="day.wheat.uniformity - grain yield")
  
  # similar to Day table IV
  require(lattice)
  xyplot(grain~straw, data=dat, main="day.wheat.uniformity", type=c('p','r'))
  # cor(dat$grain, dat$straw) # .9498 # Day calculated 0.9416
  
  require(desplot)
  desplot(straw~col*row, data=dat,
          flip=TRUE, aspect=(100*8)/(155*12), # true aspect
          main="day.wheat.uniformity - straw yield")
  
  # Day fig 2
  coldat <- aggregate(grain~col, dat, sum) 
  xyplot(grain ~ col, coldat, type='l', ylim=c(2500,6500))
  dat$rowgroup <- round((dat$row +1)/3,0)
  rowdat <- aggregate(grain~rowgroup, dat, sum) 
  xyplot(grain ~ rowgroup, rowdat, type='l', ylim=c(2500,6500))

# }