The problem with grass fires is complex, but a large part of the problem is invasive annual grasses which dry out quickly and form a fine dense mat of highly combustible material. They call it cheat grass, or “grassoline” and it has been the source of fuel for some seriously major fires in the Western states.
Re: 33 - Thanks for mentioning this.
You could also embed a sprinkler system, or a 5 foot swath of sprinklers that can go on in case of a fire and sprinkle the cheat grass.