May a municipality pass an ordinance against using land for agricultural purposes, which in effect would disallow use value assessment of such land?

The Wisconsin Department of Revenue answer is yes. The Department has stated that a municipality may enact such an ordinance, based on reasonable conditions. The legality of such an ordinance, and administration of it, would be on a case by case basis. If land was devoted primarily to a qualifying agricultural use under Wis. Admin. Code, sec. Tax 18.05(1) during the prior production season and was compatible with agricultural use on January 1 of the current assessment year, even if in violation of ordinance, easement, or contract, the land must be classified as ag land for the current assessment year. The ag classification would apply until such time that the land is no longer devoted primarily to a qualifying agricultural use.