Iowa Code § 29A.11
There shall be an adjutant general of the state who shall be appointed and commissioned by the governor subject to confirmation by the senate and who shall serve at the pleasure of the governor. The rank of the adjutant general shall be at least that of brigadier general and the adjutant general shall hold office for a term of four years beginning and ending as provided in section 69.19. At the time of appointment the adjutant general shall be a federally recognized commissioned officer in the United States army or air force, the army or air national guard, the army or air national guard of the United States, or the United States army or air force reserve who has reached at least the grade of colonel and who is or is eligible to be federally recognized at the next higher rank.
Iowa Code § 29A.11
Confirmation, see §2.32