day.wheat.uniformity {agridat} | R Documentation

## 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

### Source

James Westbay Day (1916). The relation of size, shape, and number of replications of plats to probable error in field experimentation. Dissertation, University of Missouri. Table 1, page 22. https://hdl.handle.net/10355/56391

### 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))

    ## End(Not run)

[Package agridat version 1.16 Index]