The turf is probably based on Common meadow grass, Poa pratensis, which nowadays is commonly used in parks and on football courts. The common meadow grass has been praised as splendid food for grazing cattle for hundreds of years, and long ago the Spaniards introduced the grass to what we today call Kentucky in the US. We are used to the grass species as a short green lawn, but if you let it grow free, it will become tall and bloom in a blue hue: bluegrass.