GENERAL REMARKS ON FORAGE GRASSES 1 5 



regions. In the southern portion of the Great Plains, 

 Johnson grass is an important factor in much of the 

 region that is essentially semiarid. 



Arid Region 



This includes all that portion of the United States 

 that is too dry for the growing of crops without irrigation. 

 From the agronomic standpoint, it includes the arable 

 land of this region to which irrigation water is supplied. 

 Under irrigation, practically all kinds of crops can be 

 grown, the regional distribution being limited or modi- 

 fied by temperature. The most important forage crop 

 of the irrigated region is alfalfa. Timothy is grown in 

 the arid region of Washington and some other forage 

 crops are occasionally cultivated in limited quantities. 



Region of Winter Rains 



This region lies on the Pacific Slope including the 

 foothills of California west of the Sierras and extending 

 north to Washington and Western Idaho. It lies east of 

 the humid region already mentioned, which extends from 

 northwestern California to Puget Sound, and includes 

 the Palouse region of eastern Washington. As the rains 

 come in the winter and the winter temperature is com- 

 paratively high, this season is utilized for the growing of 

 crops, though the summer may be very dry. The most 

 important crop of this region is small grain. Large 

 quantities of grain are grown for forage, the product being 

 called grain hay. This grain hay is, except alfalfa, 

 almost the only hay on the market of much of this 

 region. 



