Nice finds! I have to try some sports fields around here. We have lots of soccer fields throughout the area, and three highschools with fottball/baseball fields, all with bleacher stands. The only sports field I ever hunted was a city owned public field that dates back to the thirties. Did well with older coins, clad and a few tokens, but no jewelry and TONS of pulltabs and bottlecaps.
Keep at that field, there's bound to be much more!