40 DRY-FARMING 
August. May and June are generally the months 
of least rainfall.”’ 
“The Northern Rocky Mountain and Eastern Foot- 
hills Type. — This type is closely allied to that of 
the plains to the eastward, and the bulk of the rain 
falls in the foothills of the region in April and May; 
in Montana, in May and June.” 
“The Plains Type.— This type embraces the 
greater part of the Dakotas, Nebraska, Kansas, 
Oklahoma, the Panhandle of Texas, and all the great 
corn and wheat states of the interior valleys. This 
region is characterized by a scant winter precipita- 
tion over the northern states and moderately heavy 
rains during the growing season. The bulk of the 
rains comes in May, June, and July.” 
This classification, with the accompanying chart 
(Fig. 14), emphasizes the great variation in distri- 
bution of rainfall over the dry-farm territory of the 
country. West of the Rocky Mountains the precipi- 
tation comes chiefly in winter and spring, leaving 
the summers rainless; while east of the Rockies, 
the winters are somewhat rainless and the precipi- 
tation comes chiefly in spring and summer. The 
Arizona type stands midway between these types. 
This variation in the distribution of the rainfall re- 
quires that different methods be employed in storing 
and conserving the rainfall for crop production. 
The adaptation of cultural methods to the seasonal 
distribution of rainfall will be discussed hereafter. 
