Split Plot/Mixed Model Analysis

#1
Hi,

I have a data set that has several variables. I believe it would be most appropriate to do a split plot or mixed model type analysis. It is measuring yield with variables such as plot(these are the replicates), township(location of sub study), year(was conducted over two years thought the types and townships are not all the same), hybrid(there are about 10 of these each year but about 4 of them are different in each year), and treatment(everything in the study was expose to a fertilizer and a control).

Right now I believe the plot would be my random effect nested with township and year with all the other variables as fixed effects?