While on this topic, I haven’t tested this specifically yet, but my guess is that with the produce yield, the 104% is a bonus from the default of 1 produce item, i.e. a crop with 104% should always yield 2 items of produce, with an additional 4% chance of a 3rd item of produce.
The farming epic, depending on how it stacks, probably increases that to 124.8%. I.e. always 2 drops and 24.8% of the time a 3rd drop.
But I am only making an informed guess here, based on the number of produce I have received from crops I have planted and harvested so far.