472 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 1915. 



Table I. — Brief summary of construction results — Continued. 



Item. 



MATERIALS HANDLED. 



Excavation: 



Earth 



Indurated, 

 Rock 



Total. 



Volume placed in dams: 



Masonry 



Earth 



RockflU and crib 



Total. 



Riprap 



Paving 



Concrete 



Cement 



Unit. 



Cubic yards. 



do 



do 



.do. 



.do. 

 .do. 

 .do. 



Cubic yards . 

 Square yards. , 

 Cubic yards.. 

 Barrels , 



Number or 

 quantity. 



115,599,284 

 7, 585, 948 

 6,964,136 



130,149,368 



1,992,502 



9,231,109 



978, 474 



12,202,085 



1,023,398 



615,583 



2, 674, 977 



2,501,382 



CROPS. 



The irrigated lands are already producing an annual crop worth 

 upward of $16,000,000, which should be steadily increased by more 

 intensive farming as well as by the development of additional land. 

 In 1914 the farmers on the Government projects harvested irrigated 

 crops from over 700,000 acres. The 60,000 acres listed as irrigated, 

 but not cropped, represent mainly young fruit trees and newly 

 seeded alfalfa. 



Alfalfa dominates all crop statistics from the irrigated areas (pi. 2, 

 fig. 1). It occupies nearly half the cropped acreage and yields over 

 one-third the total crop value. Its many virtues readily explain this 

 popularity. Once established, or a " stand " secured, it is a hardy 

 plant and continues almost indefinitely to furnish good annual yields 

 without reseeding. It gives several yields or cuttings each year. It 

 is a legume with the peculiar power of drawing from the atmosphere 

 the nitrogen in which the soils of the arid region are often deficient, 

 and leaves behind more than it found of this most valuable of plant 

 requirements. It is the deepest of subsoilers, penetrating with its 

 many roots to a remarkable depth for the other essential elements of 

 plant growth and improving the physical condition of the soil. It 

 furnishes a hay of superior quality for conditioning and fattening 

 stock, so effective in fact that its medicinal value is now being 

 utilized for humans. 



A wide variety of other crops are grown on the Government proj- 

 ects — ^hays, cereals, fruit, sugar beets, and cotton, as well as garden 

 products. Barley is the leading cereal, largely replacing corn in 

 importance in comparison with middle western farming. A con- 

 siderable area is devoted to grains little seen in the humid States 



