I'm an ecology grad student struggling to confirm proper analysis for the following experimental design:
I identified 3 spatial blocks, each containing the same 3 plant types (tree, grass, shrub). There was only a single representative of each plant type within each block (9 representatives total). I measured %nitrogen of leaf tissue 10 times (date) with an irregular frequency on the same representatives.
I am interested in the plant type effect & the interaction effect of plant type & date. I would like to know if there was an effect of block and/or date. I include subject to account for its respective variation.
I believe the following model would be appropriate:
%nitrogen ~ (1|Block) + (1|Block:Subject) + (1|Date) + Vegetation + (1|Vegetation:Date)
...such that %nitrogen = response; Vegetation = fixed factor; & Block, Subject, & Date are random factors (as well as all interactions containing a random factor)
Is my nesting appropriate? Are my factor designations for "random"/"fixed" appropriate?