In the hunter ring, where there is both sand (or synthetic) and grass footing, is there anything that keeps the sand footing from mixing into the grass? If you were to set up a similar arena, how would you keep your expensive footing from blending into the grass or would that even be an issue?
Second question, are there ever issues with horses stumbling at the interface of the grass and sand?
I've never seen it be a problem unless the weather has interfered which it often does at Upperville...
and in answer to your first question, I rode at a barn for years w/ a grass ring... eventually the owner wanted sand footing which she just dumped on top... and then a few years later a bunch of us got together and got more footing for her as a gift.. I know some of you are thinking OMGoodness they're bonkers where was the footing expert, didnt they do any ring prep.. Nope she and we didn't... and guess what we really never had any issues w/ soundness (save the odd stone bruise/abscess)..