2 BULLETIN 1020, U. S. DEPARTMENT OF AGRICULTURE. 



The investigation was confined to the wheat area of the central 

 part of the American continent, the so-called Big Wheat Belt, 

 extending from northern Texas on the south to Manitoba and Sas- 



\SPff/NG W//EAT 



\W/nter Wheat 



s-Zo'-* Annua/ Fafnfa// 

 "HC/Y/'es ^-Ra/'/roacfs 



Fig. 1. — The wheat belt of the United States. 



katchewan on the north, and, in irregular contour, from the Missis- 

 sippi River on the east to the arid belt which runs south from east- 

 ern Montana to New Mexico. There are two principal wheat-pro- 



