I wouldn't worry about crops, traditional or otherwise. Many people
have hobby farms and market gardens/farms here. This is one of the best places in the US to do that.
Some people, who I've heard on the podcasts but who shall remain nameless, have said that they think
that asking for forgiveness is a better strategy than asking for permission on the earthworks
. This is a very tricky area. You might call Washington County and ask about a friend who has a "language problem but needs to know about the rules." Let them assume that the language problem is a lack of knowledge of English rather than not wanting to say who you are. I would also talk to others here who have done this or are considering. Have you contacted the Forest Grove Grange
? I've found them to be really interesting and helpful, particularly for what you're trying to do.