So every 3 turns I've got to put them on the market? Really?

On FFA I had ~100-200k bushels on hand for most accounts, and they were still short. ALL of them.

What is the formula for decay?

EDIT: So I've now confirmed what Marshal said. Every ~500,000 bushels on hand means ~500 less bushels produced per turn, even if you have 50,000 on hand, you will produce 50 less.

Is this really how decay is supposed to work? I thought it was beyond a certain threshold that things start to decay, not 24/7.