baker.barley.uniformity {agridat} | R Documentation

## Uniformity trials of barley, 10 years on same ground

### Description

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. http://doi.org/10.2134/agronj1952.00021962004400050011x

### Examples

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

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

    if(require(desplot)){
      desplot(yield~col*row|year, data=dat,
              aspect = 513/827, # true aspect
              main="baker.barley.uniformity - heatmaps by year")
    }
    if(require(desplot)){
      desplot(yield~col*row, data=dat2,
              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
    if(require(reshape2)){
    mat <- acast(dat, row+col~year)
    round(cor(mat, use='pair'),2)
    }

[Package agridat version 1.16 Index]