When the Seattle Mariners play their home opener Thursday, some of the dirt on the infield will have come from 2,500 miles away, in Pennsylvania. Baseball teams used to get any old dirt for infields and pitchers mounds, scooping soil from a nearby hillside or riverbed. Now, egged on by specialist baseball-soil suppliers, they apply nearly as much science to the dirt as they do to the pitching rotation. They demand just the right mixture of sand, clay and silt to provide a smooth, predictable surface—even if that means dirt...

Source: Wall Street Journal March 26, 2018 15:00 UTC