Why isn't my crop being fertilized?

I have two set-ups for crops for two different fields. In the large crop field, my set-up is like this:

F: Fertilizer, C: Crop, -/|: Furrow

F-F-F-F
|     |
F   F F
|   | |
F-F-F F
      |
F-F-F-C

This set-up works, the crop is consistently showing signs of fertilization and I pull increasingly higher starred crops from it.

My other set-up, which is placed in one of the more significantly smaller fields isn’t working.

F
|
F-F-C

It’s been two seasons and the fertilizer sticks haven’t shown any signs of dropping levels. I’ve pulled the crop a couple times to check if the fertilizer is working, but it isn’t. Is there any reason why my second set-up isn’t working?