﻿IREIGATION AT UNIVERSITY FAfiM, DAVIS, CAL. 7 



Summary of results of <tlf<ilf<i irrigation investigations, 1910, 1911, and 1912. 



Depth of water 

 applied. 



Yield 



in tons per 

 acre. 



Valuo of hay per 

 acre at $7 per ton. 



Cost of production. 



Net pro/it per acre. 



1910 



1911 



1912 



1910 



1911 



1912 



1910 



1911 



1912 



1910 



1911 



1912 



Inchca. 

 



3.85 



4.75 



6.02 



7 52 



0. 52 

 6.51 

 7.i»2 

 S. 32 

 9.43 

 9.38 

 8.87 

 10.04 



S26. 95 

 33. 25 



$42.14 

 52.64 



S38. 64 

 45. 57 

 49. 14 

 58.24 

 60. 31 

 65.66 

 62.09 

 70.20 



$8. 65 

 13.40 



$13. 50 

 19.60 



$12.40 

 17.35 

 19.85 

 24.10 

 27. 35 

 28. 10 

 28.80 



$18.30 

 19. 85 



$28. 64 

 33. 04 



$26. 24 



is 



28. 22 



29.29 



24 



0.00 

 7.53 



7.58 

 8.45 



8.38 

 9.61 

 9.33 

 9.64 



42. 00 

 52.71 

 53. 00 

 59.15 



58. 60 

 67.27 

 65. 31 

 67.48 



18.90 

 23.15 

 24.15 

 27.80 



24.20 

 27. 85 

 28.05 

 30.25 



23.10 

 29.50 

 28.91 

 31.35 



34. 46 

 39. 42 

 37. 26 

 37. 23 



34. 14 



30 



38. 96 



36 



48 



37.56 

 33. 29 



60 



36. 63 















Note. — Labor of production figured at $2.25 per ton. Water figured at $1.70 per acre- 

 foot. Labor for irrigation figured at 50 cents per acre per irrigation. While the value 

 of the hay is figured at $7 per ton for each of the three years 1910, 1911, and 1912, the 

 local value in 1912 was $11 per ton. 



The accompanying diagram (fig. 2) shows the average yields in 

 tons per acre for the three years, with the corresponding depths of 

 water applied, and figure 3 shows the average yield in tons per acre 

 for each cutting from the unirrigated alfalfa and from the checks 

 given 30 inches in four 7^-inch ap- 

 plications. 



The first diagram shows a very 

 uniform increase in yield up to 30 

 inches of water applied, above 

 which the increase is very small, 

 and in the case of 36 inches ap- 

 plied a slight decrease is shown, 

 although the maximum average 

 yield was produced by a total of 

 48 inches applied in four 12-inch 

 irrigations. 



The first half of the diagram 

 shown in figure 3 illustrates the 

 gradual decrease in yield in each 

 succeeding crop where no water is 

 applied, showing the need of irri- 

 gation after the first crop has been 

 removed. When this first half is 

 compared with the other half of 

 the diagram the result of irrigation is apparent. In each of the 

 three seasons the maximum yield was produced in the third crop, 

 probably because of more favorable growing conditions during June 

 and the first part of July in which this crop was grown. 



9 

 6 



Id 



a. 



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TOTAL DEPTH OF WATER IN INCHES 



O 



12 



18 



24- 



30 



36 



4-8 































































































































































































































































??!1' - 



W ' 



Fig. 2. — Average yield of alfalfa, 1910, 

 1911, and 1912, using different quan- 

 tities of water. 



