412 Tthrtieth Annual Report 



1. Feeds used in sheep feeding experiments by Animal Husbandry Depart- 

 ment. 2. Full bloom; many seed pods; relatively few buds. 3. Also called wire 

 grama; Santa Rita pasture March 16, 1919; no cattle' grazed last year; % 1918 

 growth, Vi older, would probably be eaten in this proportion; seeds fallen; stem 6 

 to 8 inches high. 4. New growth starts on sides of old stems; V4, lower stems re- 

 jected, sample 5 to 7 inches long. Old growth, 2 or 3 years old containing 14 stem 

 towards roots; 2 to 4 inches long. 5. Fine clean stems; 5 to 10 inches long; all 

 seeds fallen; perhaps one-tenth old stem. 6. Tall and co.arse; reddish; one-third 

 16 inches long, few seeds; one-third 12 inches long, no seeds; one-third 8 Inches 

 long, no seeds. 7. Entire plant with roots twisted off. S. Pods almost mature, 

 containing much pvilp. 9. Plants pulled, ropts and lower stems cut off; some 

 seeds had fa len; .'-■ample would represent average forage a'out March 16. 10. Pulp 

 of the yucca leaf after the fiber had been removed for commercial purposes. 



11. Collected August 9, 1919; in head; knee high; just passing pollen stage. 



12. Collected August 9, 1919; waist high; past blooming. 13. Collected August 9, 

 1919, nearly waist high; past pollen stage. 14. Feeds used in steer feeding ex- 

 periments by Animal Huslandry Department. 15. Old grama grass from range 

 south of Elgin: stock apparently starving; 7491 heads and tops of stems; 7492 bot 

 lorn leaves from base of old plants. 



THE SALTON SEA 



In 1907 the Department undertook, in cooperation with the 

 Desert Botanical Laboratory of the Carnegie Institution, a study of 

 the changes in the chemical composition of the Salton Sea as evapo- 

 ration took place after the closing of the break in the Colorado 

 River. Annual analyses for ten consecutive years were made, but 

 owing to the pressure of war work and the belief that less frequent 

 anayses from that time would suffice, the eleventh sample was not 

 taken till June 17, 1919. The analysis of this sample has been 

 made by the chemist as time would permit. Since these analyses 

 have developed wide scientific interest and have not been published 

 in collected form since the eighth analysis, they are given here in 

 Table VI. 



Several phenomena have been observed and reports published 

 by this Station and the Carnegie Institution. Three substances 

 have been disappearing unmistakably from the water : Calcium car- 

 bonate, potassium, and phosphorus. The calcium carbonate has 

 been accounted for in the formation of tufa, notably on mesquite 

 brush that had been submerged when the Salton Sink filled with 

 water. No adequate explanation of the fate of potassium and phos- 

 phorus has yet been made. At the suggestion of the writer, 

 Mr. S. W. Griffin undertook a comparison of the potassium and 

 phosphorus content and the potassium-sodium ratio in the tufa on 

 the mesquite with the tufa from the ancient sea at Travertine Point. 

 The ancient tufa contained potassium .20 percent, sodium .16 per- 

 cent; the recent tufa, potassium .19 percent, sodium 1.27 per cent. 

 It must be noted however, that the mesquite branches bearing the 

 recent tufa were removed from the salty water and dried without 

 rin«;ing, while the ancient tufa has been exposed to the weather 

 perhaps for centuries. Nevertheless, the potassium-sodium ratio 

 in the recent tufa is 1 : 6, while the water from which it was removed 



