Here in my part of the world to get the benefits of a cover crop that all you warm climate farmers talk about we have to fly our seed onto green growing corn the middle of august.  If I wait until after harvest (mid to late October) I may or may not get a stand and very little soil holding effect.

So what is the difference if I fly on 2 bushels of oats, or what ever cover crop of choice, or not using a full season grass herbicide and letting the foxtail and Johnson grass grow in August?

Wouldn't I get the same rotational and grown cover effects as oats or rye?  Besides it saves me the time and money of seeding a cover crop and less herbicide expense.