agridat (version 1.25)

garber.multi.uniformity: Uniformity trials of oat hay and wheat grain

Description

Uniformity trials of oat hay and wheat grain, at West Virginia Agricultural Experiment Station, 1923-1924, on the same land.

Format

A data frame with 270 observations on the following 4 variables.

row

row

col

column

plot

plot number

year

year

crop

crop

yield

yield (pounds or bu/ac)

Details

The experiments were conducted at the West Virginia Agricultural Experiment Station at Maggie, West Virginia.

Note, Garber et al (1926) and Garber et al (1931) describe uniformity trials from the same field, but the experimental plot numbers in the two papers are different, indicating different parts of the field for the two papers.

The data from 1923 and 1924 are given in Garber (1926).

The data from 1927, 1928, 1929 are given in Garber (1931).

All the data were given in the source papers as relative deviations from mean, but have been converted to absolute yields for this package.

Paper #1 - Garber (1926)

Each plot was 68 feet x 21 feet. After discarding a 3.5 foot border on all sides, the harvested area was 61 feet x 14 feet. The plots were laid out in double series with a 14-foot roadway between the plots. For example, columns 1 & 2 were side-by-side, then 14 foot road, then columns 3 & 4, then 14 foot road, then columns 5 & 6.

Note: The orientation of the plots (68x21) is an educated guess. If the orientation was 21x68, the field would be extremely narrow and long.

Field width: 6 plots * 68 feet + 14 ft/roadway * 2 = 436 feet

Field length: 45 plots * 21 feet/plot = 945 feet

Garber said: "Plots 211 to 214, and 261 to 264, [note, these are rows 11-14, columns 5-6] inclusive, were eliminated from this study because of the fact that a few years ago a straw stack had stood on or in the vicinity...which undoubtedly accounts for the relatively high yields on plots 261 to 264, inclusive."

1923 oat hay, yield in pounds per acre

The data for the oat hay was given in Table 5 as mean-subtracted yields in pounds per acre for each plot. The oat yield in row 22, column 5 was given as +59.7. This is obviously incorrect, since the negative yields all end in '.7' and positive yields all ended in '.3'. We used -59.7 as the centered yield value and added the mean of 1883.7 (p. 259) to all centered yields to obtain absolute yields in pounds per acre.

1924 wheat, yield in bushels per acre

The data for the wheat was given in bushels per acre, expressed as deviations from the mean yield (15.6 bu). We added the mean to all plot data.

Paper #2 - Garber (1931)

The year and crop was 1927 corn, 1928 oats, 1929 wheat. The data given in the paper were percent-of-mean. We converted the data back to absolute yield

The field is 10 plots wide, 84 plots tall.

Field width: 10 plots * 68 feet + 4 roads * 14 feet = 736 feet.

Field length: 84 plots * 21 feet + 3 roads * 14 feet = 1806 feet.

References

None

Examples

if (FALSE) {

library(agridat)
  
  data(garber.multi.uniformity)
  dat <- garber.multi.uniformity

  ## aggregate(yield~year, data=dat, FUN=mean)
  ##   year      yield
  ## 1 1923 1883.30741
  ## 2 1924   15.58296
  ## 3 1927   76.28965
  ## 4 1928   32.81415
  ## 5 1929   19.44650

  libs(desplot)
  desplot(dat, yield ~ col*row, subset=year==1923,
          flip=TRUE, tick=TRUE, aspect=945/436, # true aspect
          main="garber.multi.uniformity 1923 oats")
  desplot(dat, yield ~ col*row, subset=year==1924,
          flip=TRUE, tick=TRUE, aspect=945/436, # true aspect
          main="garber.multi.uniformity 1924 wheat")
  desplot(dat, yield ~ col*row|year, subset=year >= 1927,
          flip=TRUE, tick=TRUE, aspect=1806/736, # true aspect
          main="garber.multi.uniformity 1927-1929")

  # Correlation of same plots in 1923 vs 1924. Garber has 0.37
  # cor(subset(dat, year==1923)$yield,
  #     subset(dat, year==1924)$yield ) # .37

  # Garber 1931 table 2 has .58, .20
  # cor(subset(dat, year==1927)$yield,
  #     subset(dat, year==1928)$yield, use="pair" ) # .58
  # cor(subset(dat, year==1927)$yield,
  #     subset(dat, year==1929)$yield, use="pair" ) # .19

}