I also live in SW Iowa and I have very little trouble getting permission to call predators. Just start knocking on doors. I also like to talk to the rural mail carriers and county road maintenance people. They often see coyotes crossing the road.
I make it a point to tell the landowner that I will never drive my vehicle in on their land. I also ask them if they have any livestock out in pastures that I need to be aware of. This is real valuable information if it is calving time. Don’t forget to ask the property owner if they have been hearing or seeing any coyotes, fox, etc.
Many landowners know very little about calling predators and some are interested in how it’s done. I blow a call or two for them or let them listen to my E-caller.
If they give me permission to hunt I offer to let the landowner go out with me and do the shooting if he or she wants to. Very few of them take me up on the offer, but that’s ok too.
If I am successful at harvesting a critter on their property I always stop and show them what I shot. One or two dead coyotes in the back of my pick-up truck is usually a sure way to get invited back.
I have even had landowners call other farmers and tell them about me and send me to their homes to talk with them about hunting.
One last point, I never ask a landowner if I can hunt predators at night until I have hunted on his property a number of times and they get to know me fairly well.
Also don’t forget to send out those Christmas cards to property owners you hunt on.