A Graphic Summary of Americcm Agriculture. 



29 



Fig. 24. — Over two-thirds of the corn acreage of the world is in the United States, 

 nearly all east of the line of 8 inches mean snmmer rainfall and south of the line of 

 66° mean summer temperature. Nearly 90 per cent of the acreage of corn for grain 

 in the United States is in the Corn Belt, the Corn and Winter Wheat Region, and the 

 Cotton Belt. In these three regions corn constitutes about one-third of the acreage of 

 all crops. In the Corn Belt it is dominant, contributing nearly two-fifths of the acre- 

 age and half of the value of all crops. Hay, associated with spring oats in the northern 

 portion and with winter wheat in the southern portion, are the other important crops 

 in the Corn Belt. (See Figs. 29, 32, and 38.) 



