William Steel, Frontiersman

When William Steel, Frontiersman enters the battlefield, search your library for a basic land,
place it onto the battlefield tapped, Aggrigate.
{t}: Aggrigate-"Place a crop counter on target
land you control. Lands with a crop counter are croplands in addition to their other types".
Croplands you control tap for an additional mana
of any color it could produce.