﻿IRRIGATION AT UNIVERSITY FARM, DAVIS, CAL. 



climate not more than one-half of the stand can be expected to sur- 

 vive through the summer. 



(2) Heavy spring irrigations, when followed by long periods 

 throughout the summer without water, did not benefit alfalfa. Exam- 

 ination of the root growth under these conditions shows that water 

 applied to the little plants in the early spring produces a root growth 

 outwardly along the surface of the soil rather than downward, and 

 when this is followed by long dry periods, the soil drying out leaves 

 the young plant stranded above the moisture zone. Far better results 

 were obtained by delaying irrigation until the root growth was well 

 established, and even until the little plants seemed to be stunted and 

 suffering for moisture. Well-developed, deep-rooted plants mean 

 heavier yields. 



(3) Late and very late summer irrigations tend to produce sturdier 

 plants and heavier yields the following summer. 



(4) After the root growth is well established, the growth may then 

 be forced by frequent and, if the soil will stand it, heavy irrigations. 



DUTY OF WATER FOR ALFALFA, 1910, 1911, AND 1912. 



The investigations during the first year's growth of the alfalfa had 

 naturally destroyed the uniformity of the stand, making it necessary 

 to reseed the whole area. Early in March the ground was thoroughly 

 disked, cross- disked, and harrowed to a depth of 2 inches. It was 

 then reseeded, 20 pounds of Utah seed per acre being drilled in at 

 right angles to the seeding of the year before. This seed was brought 

 up by the early spring rains and at the time of the first cutting on 

 April 21 a very uniform stand covered the whole area. 



The previous year's work had shown that the water supply from 

 the ditch system was inadequate for experimental work, and the 

 pumping plant was installed and used in all subsequent work, the 

 ditch system being abandoned. 



The following schedule for irrigation was outlined and followed on 

 all but three of the checks in 1910 and 1911 : 



Schedule of irrigation of alfalfa, 1910 and 1911. 



Number of plat. 



Area. 



Depth of 



water 

 applied. 



Schedule. 



1,2,3,4 



Acres. 

 0.822 

 .536 

 .293 

 .652 

 .960 

 .920 



.920 



1.000 



.573 

 1.000 

 .513 



Inches. 



No irrigation. 



9,10,11 





Do. 



8,12. 



12 

 24 

 30 

 30 



30 

 36 



36 



48 

 48 



6 inches after first and second cuttings. 

 8 after first, second, and third cuttings. 

 7i after first, second, third, and fourth cuttings." 



7,13 



22,23,24,25 



17,18,19,28 



20,21,26,27 



tings; 3f inches before second, third, fourth, and fifth 

 cuttings. 



33 



cuttings. 



6,14 



cuttings. 

 9 inches after first, second, third, and fourth cuttings. 

 12 inches after first, second, third, and fourth cuttings. 

 Do 



32 



5,15 







