Northern Iowa (2-1) had four TD runs with three in the first quarter to jump to a 21-0 lead.
Cal Poly (1-2) answered with its first touchdown early in the second, but the Panthers added another before halftime and stretched the lead to 34-7 early in the fourth.
Daurice Fountain led the Panthers receiving unit with eight catches for 123 yards. Braden Lehman caught Bailey's only TD pass, a 7-yarder in the second quarter. Bailey finished 15 of 25 for 218 yards with 11 carries for 57 yards.
AP College Football website: www.collegefootball.ap.org