agridat (version 1.8.1)

archbold.apple: Split-split plot experiment on apple trees

Description

Split-split plot experiment on apple trees with different spacing, root stock, and cultivars.

source

D Archbold and G. R. Brown and P. L. Cornelius. (1987). Rootstock and in-row spacing effects on growth and yield of spur-type delicious and Golden delicious apple. Journal of the American Society for Horticultural Science, 112, 219--222.

Details

In rep 1, the 10-foot-spacing main plot was split into two non-contiguous pieces. This also happened in rep 4. In the analysis of Cornelius and Archbold, they consider each row x within-row-spacing to be a distinct main plot. (Also true for the 14-foot row-spacing, even though the 14-foot spacing plots were contiguous.) The treatment code is defined as 100 * spacing + 10 * stock + gen, where stock=0,1,6,7 for Seedling,MM111,MM106,M0007 and gen=1,2 for Redspur,Golden, respectively.

References

Cornelius, PL and Archbold, DD, 1989. Analysis of a split-split plot experiment with missing data using mixed model equations. Applications of Mixed Models in Agriculture and Related Disciplines. Pages 55-79.

Examples

dat <- archbold.apple

# Define main plot and subplot
dat <- transform(dat, rep=factor(rep), spacing=factor(spacing), trt=factor(trt),
                 mp = factor(paste(row,spacing,sep="")),
                 sp = factor(paste(row,spacing,stock,sep="")))

# Due to 'spacing', the plots are different sizes, but the following layout
# shows the relative position of the plots and treatments. Note that the
# 'spacing' treatments are not contiguous in some reps.
desplot(spacing~row*pos, dat, col=stock, cex=1, num=gen,
        main="archbold.apple")

library(lme4)
m1 <- lmer(yield ~ -1 + trt + (1|rep/mp/sp), dat)
print(VarCorr(m1), comp=c("Variance","Std.Dev.")) # Variances/means on page 59
## Random effects:
##  Groups      Name        Variance Std.Dev.
##  sp:(mp:rep) (Intercept)  193.31  13.903
##  mp:rep      (Intercept)  203.78  14.275
##  rep         (Intercept)  197.32  14.047
##  Residual                1015.28  31.863

## library(HH)
## interaction2wt(yield~spacing+stock+gen, dat)