BULLETIN 307, U. S. DEPARTMENT OF AGRICULTURE. 



influences vary in amount from only slight injury to total crop failure 

 and in extent from restricted localities to extended areas. A year 

 seldom occurs in which as a result of these influences there is not 

 some restriction to the growth and development of the corn plant. 

 In favorable seasons and localities good yields are frequently ob- 

 tained, but efforts to 

 grow corn for grain 

 with the natural rain- 

 fall of this area have 

 often resulted in par- 

 tial or total crop fail- 

 ures. It is to be ex- 

 pected that the same 

 conditions and results 

 will in a large measure 

 continue to occur. 



In those localities 

 where it has been pos- 

 sible to supplement 

 the natural rainfall 

 with irrigation, corn 

 is raised with consid- 

 erable success. Fail- 

 ures which at first oc- 

 curred on account of 

 carelessness and the 

 unintelligent use of 

 water and from at- 

 tempting to grow va- 

 rieties not adapted to 

 the locality are being 

 corrected as knowl- 

 edge is gained from 

 experience. 



The part of the 

 Great Plains area 

 best adapted to corn 

 production is the 

 north-central section. 

 (Fig. 1.) In this sec- 

 tion, notwithstanding the frequent failures of corn to produce grain, 

 the area devoted to its production has increased until corn is one of 

 the most generally and widely grown crops. Corn is less successful in 

 the southern Plains area, as drought injury is more severe, on account 

 of the higher evaporation rate. Corn does not successfully compete 

 in production with the grain sorghums under these conditions, and 



Fig. 1.— Sketch map of the Great Plains area, showing the annual 

 rainfall (heavy black lines) and the region (dotted section) to 

 "which the varietal adaptations of corn discussed in this bulletin 

 apply. 



