I can provide you with some higher-detail textures for the field model if you need them.
Here are some renders of the field model we used for our animation entry:
http://web.mit.edu/~levpopov/Public/FIELD/f01.jpg
http://web.mit.edu/~levpopov/Public/FIELD/f02.jpg
If you want to have very detailed looking field while keeping the polycount low, i suggest baking in most of the lighting and shadows. Yes, it may produce some unrealistic artifacts like wrong shadows or reflections, but in my opinion its still a lot better than just flat color.