I do think it's difficult to make a convincing cornfield in N-scale but the one I did see this summer on the Cumberland Valley System of the Reids did look very convincing for me. They used the Alkem brass cornfield. It has been quite painful (literally) to install, but the result is excellent.
Marc
Do you have a photo you could share?
These are photos of Alkem Scale Models photoetched corn.
On one of my modules.
This one was on Lance Mindheim's N Scale layout
Bernie