Here I have a yield mod based on the US's realistic average yields(across the country), bulk weights and the typical sowing amount of the crops included.
The seed usage and the yields of the following crops are changed:
(straw, sadly not accurate for the USA since I can´t find the numbers to calculate the real yield for FS)
Warning: The yields are very low compared to the original yields, the seed usage is also significantly changed. For example way less seed usage for canola but way more seed usage for potatoes.
I would suggest you only use this mod on maps with large fields, otherwise it will be very hard to earn money.
Yield information by factfish.com