Wisconsin Statute Chapter Tax 18: Assessment of Agricultural Property
" An assessor shall classify as agricultural land devoted primarily to agricultural use. Land devoted primarily to agricultural use shall typically bear physical evidence of agricultural use, such as furrows, crops, fencing or livestock, appropriate to the production season. If physical evidence of agricultural use is not sufficient to determine agricultural use, the assessor may request of the owner or agent of the owner such information as is necessary"
The deadline to file for an agricultural classification is May 15th.