SPRAY IRRIGATION. 15 



at least one-half the distance between standpipes, so that the entire 

 area can be covered. There are many adjustable nozzles on the 

 market which may be screwed to the end of a hose and made to dis- 

 charge a solid stream or any degree of spray by manipulation of the 

 nozzle parts. There are two familiar designs of nozzles for this pur- 

 pose. One must be held in the hand constantly or moved about at 

 very short intervals. The other may be set in one position and al- 

 lowed to spray over a circular area. 



One of the most popular portable spray arrangements is shown in 

 figure 8. This consists of a f-inch pipe, 18 to 20 feet long, containing 

 a row of small nozzles similar to those used in overhead irrigation 

 systems. This pipe has a hose connection at one end and is supported 

 on movable tripods or on short posts which are set permanently in 

 the ground or attached to the cold frame or hot bed. In some in- 

 stances the portable spray line contains three rows of " mist nozzles " 

 set at about 45° angle with each other and 3 feet apart in the row. 

 With this arrangement the pipe can be laid on top of a cold frame 

 and a fine mist spray will cover the bed. 



The hose and portable nozzle system of spray irrigation is the 

 oldest and least efficient of spray methods. It is impossible to get an 

 even application over the entire field or under one position of the 

 nozzle. The constant attendance necessary and the liability of over 

 or under irrigation makes the cost of operation high and the results 

 dependent upon the skill of the laborer. The greatest field for this 

 type of irrigation seems to be indoor spraying, outdoor sod lands, 

 seed beds, and small garden plots. The first cost is the smallest of 

 any type of spray irrigation. 



STATIONARY-NOZZLE SPRAY SYSTEMS. 



Stationary nozzles fed by underground pressure systems of piping 

 (fig. 9) have gained favor in Florida, where the sandy character of 

 the soils makes rapid irrigation necessary. This type of equipment is 

 being used for the irrigation of truck and citrus groves. Standard 

 steel or wrought-iron pipe and fixtures are commonly used, but the 

 main feed pipe sometimes is cast iron or riveted steel. Main feed 

 pipes are run underground, leading from the water works or pump- 

 ing plant into the field. Laterals are placed 12 to 15 inches below the 

 surface in parallel lines under the entire field. At intervals of 30 to 

 50 feet risers to which the nozzles are attached are placed on the 

 lateral lines s,o that the nozzles are spaced equidistant from each other 

 in triangular form, as shown in figure 9. Figure 10 shows an under- 

 ground section of a main feed pipe, with connections to laterals. 

 Each lateral is controlled by a valve and in some cases a valve is placed 

 on each riser, so that a part of the nozzles on a line may be cut off, 



