This output was requested by the SOLUTION option. There are many ways to estimate effects in a linear
model with categorical predictors. SAS chooses to do so by alphabetizing the levels of each factor, then
assigning an effect size of zero to the last alphabetically-ordered level of each factor and its interactions. To
predict the response for, say, Fertilizer K for the Red variety, use the equation (Intercept) + (K effect) +
(Red effect) + (K*Red interaction effect), or 9.13 - 0.30 - 0.33 + 0.10 = 8.60. The t-test values listed on
the right can be used to test if certain parameters are significantly different from zero; in this case, they
compare the levels of each factor to the last alphabetically-ordered level (which is forced to be zero). The
SOLUTION statement is useful for determining how treatment effects can be contrasted or estimated within
PROC GLM.
For the interaction effects, FERTILIZ is listed first and changes levels more slowly than VARIETY. Think of
the odometer on a car; the numbers on the right turn more quickly than numbers on the left. The same is
true of SAS's ordering of interaction effects.