Split-Plot Design with Subplot Replications: A Case Study.

Split plot design (SPD) has been widely used in agricultural and biological research for many years and is well documented in both textbooks and research articles. However, the variant that involves subplot replications is seldom discussed in literature. This study presents a general experiment layout and source of variance of a split-plot design with subplot replications, and then using a field experimental dataset to demonstrate how the model should be fitted in commonly used statistical packages including JMP, SAS and R. The potential effect of missing observations is as well discussed.