If you go plantin’…
We won’t leave you wantin’…
Plenish Seed
Yes the signs that appear purely promotional are simply that; likely put up with permission of the farmer as opposed to being required. I’ve seen 2 similar situations: one when I installed geothermal heating in my house, and another on a new tree farm off the highway on my commute.
The geothermal company finished their work and left a 2x2 sign with their promotional info on a post just outside my property line advertising what they did here (it was and still is rather uncommon and of course you’d never know it from the outside of the house). I don’t remember if they asked me or not, but I just left it up for a year or so until it started flapping in the breeze and getting dirty then simply took it down. It did generate a few inquiries from passers-by and probably gave people a company name to associate with that technology, but it wasn’t a major advertising deal we’d struck or anything.
The tree farm is in a semi-arid area and lush trees springing up in beside a wheat field look out of place. The sign advertises the company’s drip irrigation system in place. it’s big enough that there probably was some discussion between the company on owners about it’s being there, but installing smaller promotional signs are often just informally requested by companies selling a product. Along the lines of “do you mind if we put up 4 signs outside your fence advertising our name?” The company would do its own installation; farmers seldom do tedious little tasks like that for other people. And probably nothing would happen if people took them down or started using them as target practice.
I have seen a couple of farms with demonstration patches. That is, a well-groomed area showing off a few rows each of three or four of a company’s varieties, open for passersby to stop and look at individual plants. I’m not a farmer, but Indiana’s in the corn belt.