118 HORTICULTURE, FORESTRY, FLORICULTURE 



losses by cultivating orchards to a depth of at least 6 inches as soon 

 as practicable after each irrigation. 



Loss of Water Due to Percolation. In all modes of wetting the 

 soil, but more particularly when deep furrows are used to distribute 

 the water, a part is liable to sink beyond the deepest roots. As a 

 rule, the longer the furrow the greater is the loss from this cause. 



One of the best ways of finding out whether much water is lost 

 by deep percolations is to dig cross trenches as deep as the feeding 

 roots go. The moisture which passes the deepest roots in its down- 

 ward course may be considered wasted. 



Removal of Waste Water. The loss of water is not the only 

 effect of deep percolation. The water which escapes in this and other 

 ways usually moves through the soil at a rather slow rate of speed 

 until it reaches some underground body of water at a lower level. 

 In case orchards have been planted at these lower levels when the 

 subsoil was dry, care should be exercised in observing the rise of the 

 ground-water level. The small post-hole auger is one of the most 

 convenient tools to use in making test wells to keep track of the be- 

 havior of the ground water. Before the deepest roots of the fruit 

 trees are submerged, artificial drainage ought to be provided. Other- 

 wise the ground water will at first lessen the yield and finally destroy 

 the trees. 



The drainage of orchard tracts usually progresses in more or less 

 distinct and separate stages. When the ground w r ater begins to be 

 a menace, the natural ravines in the vicinity are cleared of weeds and 

 other rubbish and deepened. If the ground water continues to rise, 

 the open drains are deepened and extended or else the excess water 

 is withdrawn through covered drains. Open drains in orchards 

 occupy valuable land, obstruct field work, and are expensive to main- 

 tain. Some of these objections can be lessened if not removed by 

 locating such drains along the lower boundary of the tract. When 

 this plan is followed, covered drains are frequently laid among the 

 trees and discharge into the open drains. Sometimes the source and 

 direction of the waste water which is waterlogging an orchard can 

 be traced beneath the surface. In this event it is well to try to inter- 

 cept its passage before it reaches the trees. This can be done by an 

 open drain, but a covered pipe drain is preferable. When lumber is 

 cheap, box drains may be used. Where lumber is high in price, it 

 will be more economical to use pipe drains made of either clay or 

 cement. The former is most frequently used for sizes ranging from 

 4 to 8 inches in diameter and the latter for sizes 10 inches and over. 

 The clay or tile drains are made 1 foot in length, but in using 

 cement for the larger sizes the length may be increased to 2 and 

 even 3 feet. 



The drainage of irrigated lands differ in many respects from 

 that common to the humid States of Iowa, Illinois, or Ohio. In irri- 

 gated districts the drains are larger and are laid deeper. While 4- 

 inch tile drains may be used in places, 6-inch drains are to be pre- 

 ferred, and should be considered as the smallest desirable size. The 

 depth at which they are laid ranges from 4 to 7 feet, and 5 to 6 feet 



