I don't understand your remark...
Moderator or not, a player is a player, I've been playing for more than 1 1/2 year, and I know perfectly how it works.
In addtion, it's just written on each of your units description.
What I mean is I've been a beginner, with grain problems each time I had too many troops. Then I was worrying about desertion, because I wasn't strong enough to compete with other players around, but some stopped playing soon enough, so I could start to build a farms list.
I struggled until I had built and upgraded the temple of Demeter, like everybody. Than I got secure for a while, until my army grew again out of control, so I finished upgrading the academy, and finally learnt how to live losing grain permanently.
Then they added 4% to the temple of Demeter level 1 that originally gave 0%, enhanced farms production and suppressed desertion, and I went back to positive again, then my army grew again from Persians, and here I am back to negative grain balance again, this time permanently.
The only difference with when I was a beginner, is I can fill in my granaries with only 3 raids. This gives me 70 hours autonomy to feed my troops, so they can put back desertion if they want, I don't care.
So grain feed troops, period. Apart from building and upgrading, that's their only purpose.
That's the reason why the grain balance written in red is inferior to your farms gross production. It's because the grain balance = your gross production minus your troops consumption (the other number written in red on the second line).
Else explain me WHO the hell is CONSUMING, as it's clearly written, if it's not your troops ? I'm waiting for your answer.
Troops consumption is the only reason why my grain balance is (hugely) negative. When I lose some after a combat or convert a batch to veterans with orichalcum, it raises. When I get a payout from Persians, it worsens. Easily checked. You can do the exact same ascertainment by yourself.
So I don't know what you're about by denying obviousness : it's hard to figure out. Seriously, why are you doing so ???
In additon, tell me how the hell could troop dismiss, if grain stocks reaching zero was not the criteria ???
Seriously, this is so weird I'm really waiting for your answers to these questions, as you look like you're coming from another planet...