They thought that the soil wasn't good because there were no trees. The prairies often have droughts, too. Plows couldn't cut through the prairie soil, so John Deere invented a self-scouring plow that could break the prairie sod. There were four main types of prairie grass in Illinois. They are switch grass, Indian grass, big bluestem , and little bluestem.
Switch grass has an open head.
It's also bushy, and grows in wet areas. The roots may be 11 feet deep. Indian grass grows in drier areas than switch grass. Big bluestem grows up to nine feet tall. The early settlers had to stand on their saddles to see over it.