4 BULLETIN 446, U. S. DEPAETMENT OF AGRICULTURE. 



entrance into the Columbia. From here the orchard area extends 

 northwest along the narrow valley and adjacent slopes of the 

 Wenatchee River to the town of Cashmere, a distance of about 12 

 miles. There is considerable variation of altitude throughout the 

 valley, but most of the fruit is grown in an area from 700 to 1,000 

 feet in elevation. 



Records were taken only in the vicinity of Wenatchee, Olds, 

 Monitor, and Cashmere, and all data here presented refer only to 

 orchard management in those sections, unless otherwise stated. 

 Whenever Wenatchee Valley, or 'Hhe valley," is referred to in this 

 bulletin, it has specific reference to the region in the vicinity 

 of the above-mentioned towns. However, orchards are similarly 

 managed throughout the remainder of the valley. 



CLIMATE. 



The chmate of the valley is decidedly arid and no crops are grown 

 without irrigation. The temperature during the summer is often 

 high, but not oppressive. There is considerable variation in the alti- 

 tude and the annual precipitation. Tlie orchards lie for the most 

 part between the altitudes of 700 and 900 feet. There is in the valley 

 an annual precipitation from 8 to 15 inches. Killing frosts are not 

 common during the growing season. Generally speaking, Wenatchee 

 Valley has a pleasant and dehghtful chmate that is very favorable 

 to the growing fruit. 



SOIL. 



The soils of the Wenatchee Valley are loamy, varying from "a 

 very fine silty loam through coarser grades to sandy loam." The 

 subsoil is of sand and gravel and the bedrock sandstone and shale.^ 



1 As far as origin is concerned, the soils of the Wenatchee Valley are maialy of two types, namely, the 

 broad alluvial fans which are located at the foot of the steeper slopes and which appear to the best advantage 

 in the sweeping semicircle which contains the town of AVenatchee with the neighboring orchards. At the 

 mouths of each of the several canyons these fans have been formed. The canyons have been carved mainly 

 in the upturned sandstones and clays which come originally from the granite rocks. Above the town of 

 Wenatchee, continuing up the valley, while there are occasional fans the river terraces are much more 

 conspicuous. The terraces are composed at the base of glacial bowlders and gravels. Upon these one will 

 find river gravels and sands. The soil to a depth of several feet, which has been superimposed upon the 

 gravel and sand, is largely of eolian origin and hence is of a very fine grain and retains the moisture very 

 readily. 



In general, one might say that throughout the Wenatchee Valley the bedrock is represented by upturned 

 layers of sandstones and shales of lacustrine origin. Next comes a subsoil which is very coarse at the base, 

 but grading upward into gravels and sands of river origin. The top soil, varying from a few inches to a 

 himdred feet, is of very fine grain and in the main has been carried to its present position by thepersistent 

 winds which come out of the mountains to the westward. The soilis loamy in character and variesfrom a 

 fine silty loam through coarser grades to a sandy loam. Rarely is it composed mainly of sand, but in 

 general it has the right physical properties to retain the moisture with readines s. Chemically, it is good in 

 lime, iron, and potash, but is low in nitrogen. Cover crops which will yield nitrates have very greatly 

 increased the yield of soil and such crops have come to be absolutely necessary in the older orchards. — 

 Henry Landes, State geologist, Washington. 



