I try to track on many different surfaces. But be fair to the dog. I tend to make my tracks difficult which sometimes brings my dogs confidence level down.
He isn't the most driven dog to track for food or articles so I have to motivate his brain to not get bored.
I don't know if I'd track on freshly cut field, maybe wait a couple of weeks for new growth.
One thing we've always been warned about is using wooden stakes(flags) and not the surveyor type for fields that are harvested. In case a flag is forgotten, a metal one can kill livestock if pieces are ingested.