We have several resources that should help answer your questions.
Purdue Agricultural Economic Report - about cash rent and land values
Legal Aspects of Indiana Farmland Leases and Federal Tax Considerations
Crop Share Leasing and Lease Forms (EC-210-W)
Indiana Cash Farm Lease(EC-257-W)
Flex Rent Calculator Tool User Guidelines
Purdue Crop Cost & Return Guide (ID-166-W)
What's the Right Rent? (EC-708)
Cropland Leasing Update Alan Miller
Flexible Farm Lease Agreements (Iowa State C2-21)