Okla. Stat. tit. 69 § 643
Before the board of county commissioners shall permit the use of any such machinery, the board shall require that such farm be surveyed for terracing purposes by an engineer from Oklahoma State University or by the county agent of the county, either under his supervision or by some other person competent to properly survey and lay off a terrace, who shall be approved by the board of county commissioners. Such permit for the use of the machinery shall provide that the landowner shall maintain such terrace in good condition while he owns said land. The board of county commissioners and contracting farmer or farmers shall at all times seek the advice of and cooperate with, as far as possible, the county farm agent or agents in the county.
Okla. Stat. tit. 69, § 643