310 TwENTV-SIiVKNTH ANNUAL REPORT 



tables for cement pipef ; but in the sections with the rectangular con- 

 crete boxes placed 36 feet apart the loss of head was increased 66 per- 

 cent. Later tests made on the new pipe line with circular pipe risers in 

 place of the boxes showed that the loss of head was increased 35 

 percent over the smooth, straight pipe with no outlets. 



Improvements were made in the irrigation practice at the Univer- 

 sity Farm. Lands which were laid out too long originally were cut in 

 two and a new pipe line was laid to serve the lower ends. 



IRRIGATION conference; 



An irrigation conference was held at the University January 14-15, 

 1916. Invitations were sent to irrigation engineers, managers, zanjeros, 

 and farmers, and a good attendance was secured. Six meetings were 

 held and the program included papers by delegates from the Pecos, Rio 

 Grande, Salt River, Yuma, and Imperial valleys, and the Supervisor 

 of Irrigation of the U. S. Reclamation Service. Many problems that 

 are common to all irrigated districts were discussed and much helpful 

 information was disseminated. 



SILO AT UNIVERSITY FARM 



The Department also supervised the construction of a concrete silo 

 at the University Farm. The inside diameter of the silo is 12 feet and 

 the height inside is 34 feet, of which 29 feet are above ground. The 

 walls are 6 inches thick, reinforced with hog wire fencing and a few 

 half-inch round rods. The general design was the same as that recom- 

 mended by the office of Public Roads and Rural Engineering, U. S. 

 Department of Agriculture. The base was spread and was made un- 

 L'5ually heavy on account of the low bearing power of the soil upon 

 which the silo is founded. A concrete chute was built over the doors 

 and ladder from eight feet above the ground to the top. The chute 

 has walls three inches thick, reinforced with hog wire and steel rods, 

 and was cast at the same time as the main walls of the silo. The con- 

 struction of the silo was delayed a little by the extra time needed to set 

 the somewhat complicated forms for the chute, but it is believed that 

 the added convenience of the chute w^ill more than justify the cost. 



G. E. P. Smith, 

 Irrigation Engineer. 



A. L. EngEr, 

 Assistant Engineer. 



tBulletin 55, Arizona Agricultural Experiment Station. Cement Pipe for Small 

 Irrigating Systems and Other Purposes. 



