When I worked at a ball field, often we would drag the infield with nails upside down on a 2x4, 4 of them in a rectangle shape. Sort of a way of aerating a bit. That goes with what is mentioned above. Round up worked pretty well usually. Use a large board or something to keep from spraying on the grass if you use something like round up.
Originally Posted by Adam's Lawn and Garden
So in the spring i am going to attempt to get a contract to mow the baseball and practice fields at my high school to get experience doing that kind of turf care. The landscape company that did it did a real crappy job, and the mowing company does a worse job maintaining it. So how would you get grass/weeds that has grown in the infield dirt?