8 PASTURE LANDS AND GRAZING CONTROL 



abundant, efficient systems of irrigation farming have been 

 perfected. 



The Southwest. — This region includes New Mexico, Arizona, 

 and southern Cahfornia, and is therefore characterized by both 

 high temperatures and extreme aridity. In the lower valleys, 

 citrus and similar tropical fruits, as well as other crops, are 

 grown; in the interior there is a limited amount of dry farming, 

 grazing constituting the chief agricultural industry. In nor- 

 thern Arizona the elevation (about 6,000 feet and higher) is too 

 great for successful farming, but here the forage crop is excellent. 

 On account of favorable climatic conditions in the high mountain 

 region and the proximity to winter (desert) range, sheep raising 

 is especially popular in the more rugged portions. Sheep, as 

 well as cattle and horses, thrive well on the winter annual plants, 

 such as plantain, alfilaria, peas, and various early grasses, par- 

 ticularly the highly esteemed gramas, the mesquites, the fescues, 

 and many others. 



The Rocky Mountain Region. — This region embraces Idaho, 

 the western part of Montana, Wyoming, and Colorado, and the 

 eastern part of Utah, Oregon, and Washington. The region is 

 characterized by valley and basin lands from 3,000 to 7,000 feet 

 in elevation, and by mountain ranges from 8,000 to more than 

 14,000 feet above sea level (Fig. 2). 



Because of the high elevation of the region as a whole and the 

 heavy precipitation, the lands generally are well watered. The 

 annual precipitation in the valleys and basins averages about 

 20 inches, but in the mountains it may exceed 30 inches. The 

 high elevation, however, is associated with a relatively short 

 growing season and a long, cold winter. Much of the annual 

 precipitation, therefore, comes in the form of snow. 



Except where the soil is alkaHne, it is capable of good crop 

 production. As in the Great Basin and the Southwest, the 

 superior character of the native forage, consisting mainly of 

 grasses and weeds, with browse in places, makes the grazing of 

 livestock by far the most important agricultural pursuit. For 

 the reason that the Rocky Mountain region is subject to more 

 severe weather than the Great Basin and the Southwest, and 



