Well, at least in Montana, it's just a semi-arid climate. It doesn't rain enough for farming techniques developed in western europe.
My general feeling is that a good field is usually the product of generations of work: where I grew up, you had to put drainage channels every two meters, giant ditches, endless effort to get rid of weeds, etc. It wasn't the case you could just move into unmaintained soil, especially virgin soil with shrub on it, and expect it to start producing wheat without a hell of a lot of labour.
That's compounded by the fact that farmers are basically soil-seeking missiles, and always have been. If there's a patch of really good farming land, that's probably been a lot of competition for it in the preceding centuries. If there aren't any farmers on it, there's almost always a reason.
My general feeling is that a good field is usually the product of generations of work: where I grew up, you had to put drainage channels every two meters, giant ditches, endless effort to get rid of weeds, etc. It wasn't the case you could just move into unmaintained soil, especially virgin soil with shrub on it, and expect it to start producing wheat without a hell of a lot of labour.
That's compounded by the fact that farmers are basically soil-seeking missiles, and always have been. If there's a patch of really good farming land, that's probably been a lot of competition for it in the preceding centuries. If there aren't any farmers on it, there's almost always a reason.