556 



THE 1BBIGATION AGE. 



ciay pipe is similar to that used in cities for sewers and, 

 having stronger joints, withstands a greater pressure but 

 costs more. 



A line of 

 pipe is laid about 

 2 feet below the 

 surface from the 

 feed main and 

 measuring box 

 across the top of 

 the orchard, and 

 as each row of 

 trees is passed a 

 standpipe is in- 

 serted. The gen- 

 eral plan is 

 shown in outline 

 in figure 15. Var- 



ious devices are 

 employed to con- 

 vey the water from the pipe to the surface of the ground 

 at the head of each tree row and divide it up evenly 

 among 4 to 6 furrows. One of the most common con- 

 sists of a series of standpipes. the top of each set rising 

 to the same elevation. At each change of elevation 

 special standpipes are used and in these are inserted gates 

 provided with overflows. The manner of distributing the 

 water from a standpipe to the fur- 

 rows of any one row is shown in 

 figure 16. 



Occasionally a high-pressure 

 pipe is substituted for cement and 

 clay. This is tapped at the head 

 and in line with each row of trees, 

 and a small galvanized-iron pipe 

 is inserted. These standpipes are 

 capped by an ordinary valve which 

 regulates the flow to each row of 

 trees. This method is shown in 

 operation in figure 17, where a 

 young orcjiard is being irrigated 



from ^-inch galvanized-iron standpipes connected to a 

 3-inch wooden pipe. 



Making Furrows. 



The length of the furrow is often governed by the 

 size of the orchard. The rows of citrus trees seldom 

 excetd 40 rods in leujrfh. but the apple orchard? of the 

 Northwest are larger as a rule. Even in large tracts it 



Turnout SU7fx/ 



Fig. VS. Common Sizes of Concrete Head Flumes. 



sinks readily through it, short furrows should be used, 

 otherwise much water is lost in deep percolation on the 

 upper part of the tract. Prof. H. Culbertson, of San 



Diego County, 

 Cal., after a care- 

 ful investigation 

 of this subject 

 has reached the 

 conclusion .that 

 on sandy or grav- 

 elly soil having 

 a steep slope the 

 proper length of 

 furrows is 200 

 feet, while on 

 heavier soils and 

 flatter slopes the 

 length may be 

 increased to 600 



feet. 



Fig. 14. Earthen Head Ditch Lined with Concrete. 



The grade of .furrows varies quite widely. In flat 

 valleys it is often not possible to obtain a fall greater 

 than 1 inch to 100 feet, while on steep slopes the fall may 

 reach 20 inches per 100 feet. On ordinary soils a grade 

 of 3 to 4 inches is to be preferred, and where the fall ex- 

 ceeds 8 to 10 inches to 100 feet the trees should be set 

 out in such a way as to decrease the slope of the fur- 

 rows. 



The number of furrows in or- 

 chards depends on the age of the 

 trees, the space between the rows, 

 the depth of furrow, and the char- 

 acter of the soil. Nursery stock is 

 irrigated by one or two furrows 

 and young trees by two to four. 

 A common spacing for shallow 

 furrows is 2}4 feet, while deeper 

 furrows are made 3 to 4 feet apart. 

 The general trend of orchard prac- 

 tice is toward deep rather than 

 shallow furrows, a depth of 8 

 inches being frequently used. 



The furrowing implement most commonly used by 

 the orchard.ists of Orange County, Cal.. consists of a 

 sulky frame to which are attached two or three double 

 moldboard plows. Those who prefer a small number of 

 deep furrows use a 12 to 14-inch corn lister. In figure 

 18 is shown a furrower made by attaching an arm to a 



(1 



Olrerf/ar 

 Stancf 



m 



Fig. 15. The Use of Pipes in Furrow Irrigation. 



is doubtful if it ever pays to run water in furrows more 

 than about 600 feet. Where the soil is open and water 



Fig. 16. Section of Standpipe Outlined 

 in Figure 15. 



cultivator and then fastening two shovels to the arm. 

 In the view the space between the furrows is 4^4 feet and 

 the depth is regulated by the lever arm of the cultivator. 



(Continued in October issue.) 



