IRRIGATION AND DRAINAGE 



135 



triangles with a tree at each vertex, the trees forming hexagons 

 and also groups of sevens if the center tree of each hexagon is 

 included ; hence the name ' ' equilateral, " " hexagonal, " or f ' septuple. ' ' 

 The chief advantage of this mode of planting is that it provides 

 three and often four different directions in which furrows may be 

 run. There are other advantages — the ground can be cultivated 

 in different ways and about one seventh more trees can be planted 

 to a given area 

 than is possible 

 in the square 

 method. 



In the past 

 the trees of 

 the irrigated 

 orchards have 

 been planted 

 too close. This 

 is clear even 

 to the casual 

 observer who 

 may visit the 

 deciduous or- 

 chards of the 

 Santa Clara 

 valley, Califor- 

 nia, or the 

 apple orchards 

 of the Hood 



River district in Oregon. Under irrigation systems apple trees 

 should be spaced from 30 to 36 feet apart. On the Pacific coast the 

 tendency toward wide spacing has induced many growers to insert 

 peach fillers between other slower-maturing trees, such as the apple. 

 A common practice is to set the trees in 18-foot squares, peach 

 trees alternating in every other row with the standard apple trees ; 

 the remaining rows consist of Winesap apple trees which are used 

 as fillers. As the permanent trees grow and begin to crowd the 

 fillers, the peach trees are removed. If more space is required, the 

 Winesaps are taken out, leaving the apple trees in 36-foot squares. 



LINCOLN AVENUE 



Fig. 57. 



Orchard tract under Gage Canal, Riverside, 

 California 



