Page:Tree Crops; A Permanent Agriculture (1929).pdf/25

 variable; and 10." (Fig. 1.) Ten tilled crops, and ruin has arrived!

We usually think of Illinois as level land, not subject to destruction by erosion; yet this Illinois bulletin states and shows by this map that "about 5½ millions of acres of land are subject to serious erosion." This is about 9000 square miles, an area larger than Massachusetts.

Even Oklahoma, newest of the new, so recently wrested from the Indian, who did not destroy it, has its million miles