﻿4 BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE. 



The midsummer irrigation of July 14 produced two very light 

 crops and left the plants alive but growing very slowly at the end 

 of the season. Before this first irrigation was applied the root 

 system had time to penetrate well into the subsoil and receive full 

 benefit from the irrigation after it was applied. 



The late and very late irrigations both produced one fair crop 

 besides the first light crop cut in May, and at the end of the season 

 all of the alfalfa had shown a vigorous growth, with no apparent 

 effects from the early drought, indications pointing toward a good 

 yield in the spring. 



Two irrigations. — In the plats given one early and one late irriga- 

 tion only a 2-inch growth was shown between the cutting in the 

 middle of June and the irrigation on August 10. Following the first 

 irrigation the alfalfa made a slight growth, but it was not until after 

 the second application that a substantial growth was made, which 

 produced one fair cutting in September. 



One midsummer and one late irrigation produced a fair cutting 

 in September, followed by a second and much heavier crop early in 

 November. At the time of this last cutting the stand was in very 

 good condition,, the plants being deep-rooted and sturdy. 



Two late irrigations of 9.4 and 8.9 inches, respectively, applied 

 August 1 and September 9, produced two good crops, the first on 

 September 7 and the last November 12, and at the end of the season 

 these plats had not only produced the heaviest first-season yields, 

 but contained the hardiest and best appearing plants. 



Three irrigations. — In these plats the first and heaviest irrigation, 

 applied May 29, seemed to have little effect upon the stand aside 

 from keeping it alive; but after the second application, on July 13, 

 the growth was rapid ; and following the third application of August 

 23 a heavy first-year crop was taken off October 12, and a second fair 

 crop in November, and at the end of the season the plants seemed to 

 be very well developed, indicating probable heavy yields the following 

 spring. 



Late in November plats 35, 36, and 37 were all given a very heavy 

 early-winter irrigation. This was waste water pumped onto the 

 plats during the testing out of the pumping plant, and, all told, the 

 water applied must have amounted to a depth of about 18 inches. 

 This seemed to have a remarkable effect upon the stand and was 

 directly responsible for a heavy yield with small amounts of water 

 the following summer. 



Although no definite conclusions can be drawn from a single 

 season's observations, nevertheless the results obtained point to the 

 following facts : 



(1) Without irrigation spring-sown alfalfa is uncertain in Sacra- 

 mento Valley, and under conditions of normal rainfall and moderate 



