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



The following table shows the results of the two seasons' work : 



Summary of results of irrigation of Egyptian corn. 



Season. 



Number 

 of plat. 



Number of irrigations. 



Depth. 



Yield per 

 acre. 



Value at 



$1.50 per 



100 pounds. 



Cost of 

 irriga- 

 tion. 





fl-A 

 1-B 



h-C. 



2 



[3 



None 



Inches. 



Pounds. 

 1,335 

 2,670 

 2,700 

 2,510 

 3,340 

 1,100 

 1,690 

 2,650 

 2,965 



$20. 03 

 40.05 

 40.50 

 37.65 

 50.1O 

 16.50 

 25.35 

 39.75 

 44.48 







One 



3.75 

 5.50 

 3.10 

 5.35 



$1 52 



1910 



Two 







One 



1.43 





Two 



2 60 









1911 



One 



Two 



1.8 

 4.6 

 5.7 



1.04 





2.38 





Three 



3 20 









Note. — Cost of irrigation is taken as 30 cents per acre-inch for power and attendance, plus 50 cents per acre 

 per irrigation for furrowing. 



The accompanying diagram (fig. 5) shows the results for 1911, 

 platted graphically, the yields with the corresponding amounts of 

 water applied being shown. 



With this crop, as with the Indian corn, a greater yield is pro- 

 duced in 1910, with less amounts of water applied, than in 1911, due 



entirely to a warmer spring and much 

 more favorable growing season. 



The results for 1910 show but a small 

 variation in the yields from plats 1-B, 

 1-C, and 2, and a large increase in plat 

 3. This is due to the time of irriga- 

 tion, plat 3 receiving one early and one 

 midseason irrigation, the first applied 

 before any effects of drought were 

 shown, thus keeping more or less of a 

 constant moisture percentage in the 

 soil during the entire period of growth. 

 In 1911 the yields increased quite uni- 

 formly with the increased amounts of 

 water applied, until the third irriga- 

 tion, when there was a slight falling off. When this last irrigation 

 was applied the heads were fully formed and the grain ripening, 

 and the only effect of this irrigation was probably in preventing any 

 pinching or shrinking in the grain. 



Inspection of the value column for each season shows that the 

 irrigation of this crop may be made to pay, even if 6 per cent interest 

 on an investment of $50 per acre for leveling the land and developing 

 water be added to the cost of irrigation. 



Here, as in the irrigation of other grain crops, no definite duty of 

 water can be established. The amounts of water required and the 

 time of irrigation will always vary with the season, and the intelli- 







Water Applied,- inches 





o 



1.8 



4.6 



5.7 



III 



a. 

 o 

 < 



Id 



a. 



co 

 a 



z 



O 



c 



z 



Q 

 _1 

 111 



> 



2500 

 2000 

 1500 

 IOOO 

 500 

 O 



























«i 



"i 











.8 







l 













C\J 



CO 













Fig. 5. — Yield of Egyptian corn 

 with different quantities of water. 



