Wis. Stat. § 422.210: Agricultural credit transactions.

(1) Permissible finance charges and fees. With respect to a credit transaction that it is primarily for an agricultural purpose, a creditor may not charge, collect or receive any finance charge or fee unless the charge or fee is clearly disclosed in writing to the customer and that is agreed to by the creditor and the customer.

(2) Penalty. A violation of this section is subject to s. 425.304.