﻿12 



BULLETIN 10, U. S. DEPARTMENT OF AGRICULTURE. 



The following table shows the results obtained from the three 

 seasons' work, and these are further illustrated in the diagram (fig. 

 4) in which the jdelds of grain in pounds per acre are platted, with 

 the corresponding amounts of water applied. 



Summary of results of oarley irrigation, 1910, 1911, and 1912. 



Season. 



Rainfall 



for 

 season. 



Number of plat. 



Number of irri- 

 gations. 



Depth. 



Yield per acre. 



Value. 



Cost of 



Hay. 



Grain. 



tion. 





Inches. 

 11.90 



23.18 

 9.46 



Unleveled area 



{35 



None 



Inches. 



Pounds. 

 3,120 

 3,440 

 4,460 

 1,560 



2,040 

 2,720 



3,180 

 3,740 

 680 

 1,925 

 2,480 

 3,780 



Pounds. 



1,160 



1,480 



1,840 



805 



1,108 

 1,520 



1,810 

 2,146 

 345 

 1,040 

 1,280 

 1,950 



$17.40 

 22.20 

 27.30 

 12. 08 



16.62 

 22.80 



27.15 

 32.19 

 5.18 

 15.60 

 19.20 

 29.25 





1910 



One 



3.6 



5.2 



$1.08 



36 



Two 



1.56 





Unleveled area 



(north half). 

 36 



None 







One early 



One late 



Two 



4.3 



6.4 



7.0 

 6.0 



1.29 



1911 



Unleveled area 



(south half). 

 35 



1.92 

 2.10 





,37 1 



One early 



None 



1.80 





Unleveled area 



35 1 







do 







1912 



136 1 



One 



7.35 



17.95 



2.20 





37 1 



Two 



5.38 















1 Green manured. 

 Note. — Irrigation cost figured at 30 cents per acre-inch for marking furrows, power, and attendance. 

 Grain values figured at $1.50 per hundred. Value of hay is disregarded. 



Weather records taken over the entire period of the experiment 

 show that these three years represented extremes in rainfall and gen- 

 eral weather conditions. Never- 

 theless, under all of these vary- 

 ing conditions there is not one 

 instance where the increase in 

 yield did not more than pay for 

 the cost of the water which pro- 

 duced it, the yield increasing 

 with the increased amounts of 

 water applied. 



It will be noted that in each 

 of these seasons two irrigations, 

 one of which was applied at 

 about the time the grain came 

 to a head or soon after, or one 

 late irrigation, as in 1911, pro- 

 duced a heavy yield above the 

 single early irrigation. In each 

 of these three years strong, dry- 

 ing north winds occurred about 

 the time the grain was in the 

 dough. The unirrigated and 

 early irrigated grain was badly pinched, while the presence of the 

 moisture in the checks irrigated late seemed to prevent this, pro- 

 ducing full, plump grain. 





I9I0-I9II 1912 



Water applied,-inches 







4.6 



6.1 



O 



O 



735 



17.95 



1800 



£ 1600 







< 



E 1400 



UJ 



0. 



* 1200 



Q 



z 1000 







a 800 



z 



5 600 



UJ 



> 400 



200 

 































































' 























































r- 





CO 

 < 



A. 



CM 















.0 



I 5 















.^1 















V. 



Unmanured ■ 



MANURED 



Fig. 4. — Yield of barley with different quan- 

 tities of water, on manured and unmanured 

 land. 



