Ohio Const. art. II, § 36

Laws may be passed to encourage forestry and agriculture, and to that end areas devoted exclusively to forestry may be exempted, in whole or in part, from taxation. Notwithstanding the provisions of section 2 of Article XII, laws may be passed to provide that land devoted exclusively to agricultural use be valued for real property tax purposes at the current value such land has for such agricultural use. Laws may also be passed to provide for the deferral or recoupment of any part of the difference in the dollar amount of real property tax levied in any year on land valued in accordance with its agricultural use and the dollar amount of real property tax which would have been levied upon such land had it been valued for such year in accordance with section 2 of Article XII. Laws may also be passed to provide for converting into forest reserves such lands or parts of lands as have been or may be forfeited to the state, and to authorize the acquiring of other lands for that purpose; also, to provide for the conservation of the natural resources of the state, including streams, lakes, submerged and swamp lands and the development and regulation of water power and the formation of drainage and conservation districts; and to provide for the regulation of methods of mining, weighing, measuring and marketing coal, oil, gas and all other minerals.