Here is why the DOT officer said you do not need a CDL to drive your farm truck.......
§ 383.3 Applicability
A State may, at its discretion, exempt individuals identified in paragraphs (d)(1),
(d) Exception for farmers, (1) Operators of a farm vehicle which is:
(i) Controlled and operated by a farmer, including operation by employees or family members;
(ii) Used to transport either agricultural products, farm machinery, farm supplies, or both to or from a farm;
(iii) Not used in the operations of a common or contract motor carrier; and
(iv) Used within 241 kilometers (150 miles) of the farmer's farm.