aphids: Aphids data set
In cdtRggplot2: cdtRggplot2

The is data described in Matis et al, 2008. The data set consists of five observations on cotton aphid counts on twenty randomly chosen leaves in each plot, for twenty-seven treatment-block combinations. The data were recorded in July 2004 in Lamesa, Texas. The treatments consisted of three nitrogen levels (blanket, variable and zero), three irrigation levels (low, medium and high) and three blocks, each being a distinct area. Irrigation treatments were randomly assigned within each block as whole plots. Nitrogen treatments were randomly assigned within each whole block as split plots. . Note that the sampling times are $t$=0, 1.14, 2.29, 3.57 and 4.57 weeks (i.e. every 7 to 8 days).

Time: Sampling time (in weeks). This has been slightly simplified
Water: Water level at that particular plot: Low, Medium and High
Nitrogen: Nitrogen level at that plot: Blanket, Variable and Zero
Block: The plot block: 1, 2 or 3
Aphids: The number of aphids counted