Uniformity trials of wheat in India

Uniformity trials of wheat in India.

Usage

data("iyer.wheat.uniformity")

Format

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

row

row

col

column

yield

yield, ounces per plot

Details

Data collected at the Agricultural Sub-station in Karnal, India, in April 1978. A net area of 400 ft x 125 ft was harvested by dividing it into 80x25 units 5 ft x 5 ft after eliminating a minimum border of 3.5 ft all around the net area.

Field width: 80 plots * 5 feet = 400 feet

Field length: 25 rows * 5 feet = 125 feet

In a second paper, Iyer used this data to compare random vs. balanced arrangements of treatments to plots, with the conclusion that "it is very difficult to say which [method] is better. However, there is some tendency for the randomized arrangements to give more accurate results."

Source

P. V. Krishna Iyer (1942). Studies with wheat uniformity trial data. I. Size and shape of experimental plots and the relative efficiency of different layouts. The Indian Journal of Agricultural Science, 12, 240-262. Page 259-262. https://archive.org/stream/in.ernet.dli.2015.7638/2015.7638.The-Indian-Journal-Of-Agricultural-Science-Vol-xii-1942#page/n267/mode/2up

References

None.

Examples

if (FALSE) { # \dontrun{

library(agridat)
data(iyer.wheat.uniformity)
dat <- iyer.wheat.uniformity

libs(desplot)
desplot(dat, yield ~ col*row,
        main="iyer.wheat.uniformity", tick=TRUE, 
        aspect=(25*5)/(80*5)) # true aspect

# not exactly the same as Iyer table 1, p. 241
var(subset(dat, col <= 20)$yield)
var(subset(dat, col > 20 & col <= 40)$yield)
var(subset(dat, col > 40 & col <= 60)$yield)
var(subset(dat, col > 60)$yield)
  
# cv for 1x1 whole-field
# sd(dat$yield)/mean(dat$yield)
# 18.3

} # }