You are in the same position---- financially---

-- if you sold the grain, and gifted the cash.........after the gift,  you have no cash left over, no grain, and the church has the value, ie cash.

In the case of gifting grain, after the gift..........you have no cash, no grain, and the church has the value, ie cash.

But----------- if gift the grain, you are paying no SE tax on the sale of the grain, and not having to itemize deductions to get the charitable gift deduction.

If you gift the grain............you cannot also take a charitable contribution deduction...........you would be getting a deduction twice.