As best I recall, it had to do with a rule change that stipulated that those portions of the end zone in direct contact wth the goal line and end line must be of a contrasting color, i.e. not white. (The rationale was that it would be easier for officials to determine visally if the ball had crossed the goal line or was out of the end zone.) Thereafter, it was decided to integrate a green border in those areas.
Incidentally, if you think the Boise State field is bright, take a look at some of these fields ( Sporting Colors: 10 Crazy Colorful Football Fields | WebUrbanist ).
Those are cool. Thanks for posting. I still dont like the Blue.....The Red actually didnt look bad? Not sure how that Plaid is going to work out? LSU's purple should remain IMO.