Koram have gone crazy, there now a new item (the Earth Seal) the turn a 15 farm field city in a 18 farm field city.

You’ve read it, 18 farm field ! That mean all the field of your city will be for food.

So what a 18 farm field city look like ?

Let’s do some math here :

level 20 farm = 4500/hr

Let compare the 15f vs a 18f (only 3 farmland more):

Base food output
4500 x 15farms = 67500/hr (excluding bonus)
4500 x 18farms = 81000/hr (excluding bonus)

Mill Bonus
67500 x 25%mill bonus = 16875 (15f)
81000 x 25%mill bonus = 20250 (18f)

16875 + 67500 = 84375/hr (15flag city total output excluding oasis and politic)
20250 + 81000 = 101250/hr (18flag city total output excluding oasis and politic)

Oasis
with the 3 50% oasis = 150%
67500 x 150% = 101250 (15f)
81000 x 150% = 121500(18f)

101250 + 84375 =  185625 (w/o politic) (15f)
121500 + 101250 = 222750 food/hr (almost 40k more than the 15 flag city field)

Wow 222750 of standard food output…

If we keep the idea of a old post from the art of war, with some gold you can have some thing real nice
(original post here : http://forum.koramgame.com/viewthread.php?tid=6839&extra=)

With emperor’s order (treasure bowl or token of rain), Cao cao, metal alchemy scroll and the level 10 league resource bonus you can boost you food output even more.
– emperor order provide 25% food bonus.
– Cao cao could provide another 30% food bonus because of his max 150 politic (base = 100 + 30 pol bonus generalissimo + 20 pol history of han) 
– Cao cao have a skill that increase food output by 25%
– league level 10 provide 10% bonus food output
– Metal Alchemy scroll give 5%

So  25% + 30% + 25% + 10% + 5% = 95% food bonus
222750 /hr x 95% = 211612.5/hr
222750 + 211612.5= 434362/hr

Note : that I don’t know if heroes can stack skill book with mid skill, if they can Cao Cao could have a farm skill to increase the food output even more.

Almost 450k of food per hours, with that and let say you go in the red by -150k you have a army of 600k soldier

Official news here

Note : you need to have like 10 three star epic hero to win the Earth Seal, so that mean a lot of gold …

Edit : Like Bazzz pointed out the bonus mid skill don’t stack so I modified the gold section.

Edit : Fixed the math wiht Morenzuul comment that the % bonus are always applied to your base output