I remember a book about a boy in foster care. He was placed with a couple that owned a farm or ranch. I think the boy was the only child in the house. The clearest detail I can remember was the boy and foster father moving irrigation rigs around the ranch to water all the crops. I think the setting was Oregon or Washington state, but I am not sure. I was in elementary school in the mid 1980s, and this book was in our library. Thank you for any help you can provide!