Farm Land or Not?

For 3 years we have been living here and we have been told that this land use to be a farmer's field, but what was it before it belonged to them? For 3 years I have been finding pieces of glass on one side of the front yard. They are not just clear pieces, some have prints like a plate, but they are never big enough for us to figure them out. *Well see the big yellow one, I just found it the other day on the other side of the yard and we think it might be from a flower pot or a big bowl? It is neat finding them, but is a mystery figuring them out.