Are you kidding? A sweet potato can be grown anywhere... doing so does not make it "farmland". Maybe it is considered as farmland in China where there are 1.4 billion people but just looking at the pictures in the I-Box tells you otherwise.
Get back to me after you log onto one of the Chinese web sites and get the tax records (they are available for every property in the US) and verify that the land is zoned agricultural.
Just to be clear, I understand your pointing to crops near the ZJMY swap station and calling it farm land if that was the purpose of the land before the swap station was built. But many cities have crops growing on land-locked lots as a means of raising cash for tax purposes until that land is sold or used for another purpose.
I live several miles away from a large regional hospital that was built upon land that was growing corn crops until several years ago. It was the only land available that did not have businesses or residential sub-divisions built upon it anywhere nearby.