These data arise from a split-plot experiment reported by Yates (1935) and used as an example in Pinheiro and Bates (2000) and other texts. Six blocks were divided into three whole plots, randomly assigned to the three varieties of oats. The whole plots were each divided into 4 split plots and randomized to the four concentrations of nitrogen.
References
Pinheiro, J. C. and Bates D. M. (2000) Mixed-Effects Models in S and S-PLUS, Springer, New York. (Appendix A.15)
Yates, F. (1935) Complex experiments, Journal of the Royal Statistical Society Suppl. 2, 181-247