Tis a game the banks play.

Lend money so farmer can buy farm.
Wait till bad year, farmer defaults, bank gets farm.
Bank sells farm to new buyer
(repeat)

Bankers should be lined up and shot for such practice.
But it is considered normal.

It shouldn't be considered normal.
The farmer has to grow food as well as harvest and sell it for cash, to pay back the banks. (and pay taxes)

Why is the farmer required to go so far?
Why isn't the note written in terms of bushels?

The onerous is put completely on the farmer, and the bank does nothing but some mathematical chicanery.