First a question: can PS brushes be used in Gimp? If so, how do I go about installing them?

Now to my brushes request:
I’m in need of brushes to represent grazing land for herd animals like cattle and sheep, and brushes to represent crops/farmlands. While I have a number of brushes for PS in my PSP, I only recognise mountains, trees and hills so I don’t know if I have the other two. If I don’t have them, how do I get them?