In addition to land, "the exemption extends to facilities to be used in connection with agricultural functions." Id. (citing DeCoster v. Franklin County, 497 N.W.2d 849, 853 (Iowa 1993) (livestock waste stations being used in connection with hog finishing facilities held exempt)); Helmke v. Bd. of Adjustment, 418 N.W.2d 346, 351-52 (Iowa 1988) (co-op's off-site grain storage facility held exempt). Our supreme court most recently analyzed the section 335.2 exemption in 1996, and stated:

However, regardless of the status of the land, section 335.2 anticipates that a county may consider whether a specific building or structure thereon is primarily adapted for use for agricultural purposes. SeeIowa Code § 335.2 (stating that “no ordinance adopted under this chapter applies to land, farm houses, farm barns, farm outbuildings or other buildings or structures which are primarily adapted, by reason of nature and area, for use for agricultural purposes, while so used” (emphasis added)); DeCoster v. Franklin County, 497 N.W.2d 849, 853 (Iowa 1993) (considering whether a waste storage basin on agricultural land was entitled to an agricultural zoning exemption and determining that it was); Kramer, 795 N.W.2d at 93–94 (finding that a lagoon on farmland was not entitled to such an exemption). In recommending denial of the exemption, the zoning administrator emphasized that, based on his reading of the log, the prior tenant had devoted only 2.6 hours a day to what he considered to be agricultural activities.

We have previously stated that this section confers jurisdiction on the DNR "to adopt standards . . . for the disposal of waste from [livestock confinement] facilities." DeCoster v. Franklin County, 497 N.W.2d 849, 853 (Iowa 1993) (dicta). As we noted in DeCoster, the responsibility of the DNR to adopt standards and issue licenses for the disposal of waste from confinement facilities is exclusive.

Because the finishing buildings and sewage lagoons are structures and are incident to the raising of livestock, which is farming, they are farm structures. AccordKuehl v. Cass County,Iowa, 555 N.W.2d 686 (Iowa 1996) (hog confinement facilities are farm structures exempt from county zoning); Thompson v.Hancock County, 539 N.W.2d 181 (Iowa 1995) (large hog barns are farm structures exempt from county zoning); Decoster v.Franklin County, 497 N.W.2d 849 (Iowa 1993) (hog lagoons are farm structures exempt from county zoning). Nevertheless, Township argues that the statutory language is ambiguous. It asserts that a plain language approach is improper and that summary judgment is inappropriate because a genuine issue of fact exists as to whether such buildings are agricultural buildings as opposed to farm buildings.

The State's claim for declaratory relief was also tried in equity. Therefore, our review of the trial court's decision on that claim is de novo. DeCoster v. Franklin County, 497 N.W.2d 849, 851 (Iowa 1993) (declaratory judgment tried in equity is reviewable de novo). IV. Public Trust Doctrine.

Using this definition, we have held that the exemption extends to facilities to be used in connection with agricultural functions. DeCoster v. Franklin County, 497 N.W.2d 849, 853 (Iowa 1993) (livestock waste stations being used in connection with hog finishing facilities held exempt). The Thompsons have been farming some portion of the land that they currently own or lease for the past twenty years.