358 irrigation and Drainage 



watered on but one side, and it was the yield from 

 these rows which has been used in making the com- 

 parison. 



It was also found that the first row not irrigated 

 on either side, and hence standing 45 inches from 

 the center of the water furrow, had its yield increased 

 by the watering only 7.9 bushels per acre. This 

 makes it appear that were the potatoes planted in 

 rows 90 inches apart and the water applied in a single 

 furrow between each two rows, the benefit derived 

 from the water would be much less. 



It is very clear, therefore, that in furrow irriga- 

 tion care must be taken that the water is not led 

 along lines too distant from the plants which are 

 to use it. 



Where the water is to be .allowed to run some 

 time in individual rows, and where considerable quan- 

 tities are being handled, it will often be found desir- 

 able to take it out of the head ditch into short 

 feeders which supply a certain number of rows, as 

 represented in Fig. 95, where the water in the fore- 

 ground is in the head ditch, the feeder standing next 

 sending water into 8 rows of rape, 28 inches apart 

 from center to center, from which the first cutting 

 has just been removed. 



Sugar beets, maize, and all field crops upon which 

 intertillage is practiced would be irrigated in a similar 

 manner ; but in such close planting as that above 

 on sandy loams or lighter soils, it would probably 

 be sufficient to lead water down every other furrow, 

 keeping the other rows under frequent flat cultivation. 



