Uniformity trial of corn at 3 locations in Iowa.
Uniformity trial of corn at 3 locations in Iowa.
data("bryan.corn.uniformity")A data frame with 1728 observations on the following 4 variables.
exptexperiment (variety/orientation)
rowrow
colcolumn
yieldyield, pounds per plot
Three varieties of corn were planted. Each experiment was 48 rows, each row 48 hills long, .65 acres. (A "hill" is a single hole with possibly multiple seeds). Spacing between the hills would be sqrt(43560 sq ft * .64) / 48 = 3.5 feet.
In the experiment code, K=Krug, I=Iodent, M=McCulloch (varieties of corn), 23=1923, 25=1925, E=East/West, N=North/South.
Each experiment was aggregated into experimental units by combining 8 hills, both in East/West direction and also in North/South direction. Thus, each field is represented twice in the data.
Arthur Bryan (1933). Factors Affecting Experimental Error in Field Plot Tests With Corn. Agricultural Experiment Station, Iowa State College. Tables 22-27. https://hdl.handle.net/2027/uiug.30112019568168
None
## Not run:
library(agridat)
data(bryan.corn.uniformity)
dat <- bryan.corn.uniformity
libs(desplot)
desplot(dat, yield ~ col*row|expt,
main="bryan.corn.uniformity",
aspect=(48*3.5/(6*8*3.5)), # true aspect
flip=TRUE, tick=TRUE)
# CVs in Table 5, column 8 hills
# libs(dplyr)
# dat
# summarize(cv=sd(yield)/mean(yield)*100)
## expt cv
## 1 K23E 10.9
## 2 K23N 10.9
## 3 I25E 16.3
## 4 I25N 17.0
## 5 M25E 16.2
## 6 M25N 17.2
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