Utah Code § 59-2-510

Separation of a part of the land which is being valued, assessed, and taxed under this part, either by conveyance or other action of the owner of the land, for a use other than agricultural, subjects the land which is separated to liability for the applicable rollback tax, but does not impair the continuance of agricultural use valuation, assessment, and taxation for the remaining land if it continues to meet the requirements of this part.