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WHEAT PRODUCTION ON DRY LANDS. fs 
more subject to drifting or blowing by the wind. The soil depth 
varies from 10 to 50 feet, and the texture is remarkably uniform 
throughout the entire depth. The topography, like that at Moro, 
is rolling, the entire dry-farming area of the Columbia River Basin 
being a plateau cut by dry canyons or coulees. The altitude of the 
station at Lind is 1,600 feet. 
During the years that the experiments herein reported were con- 
ducted the moisture at Lind has been far below normal and has not 
been sufficient to penetrate the soil to a greater depth than 4 feet or 
to raise the moisture content above 10 per cent, even after a season of 
fallow. The moisture content after growing a crop of winter wheat 
is about 3.S per cent in the upper 4 feet of soil. 
s 
Fic. 5.—Some of the experimental plats at the Sherman County Branch Station, Moro, Oreg. 
The altitude of the Nephi Substation is approximately 5,300 feet. 
The soil is a rather heavy clay loam derived from the weathering of 
adjacent mountain ranges. Below the third foot the percentage of 
silt and sand increases, and at about the seventh foot there is a stra- 
tum of heavy blue clay of rather high moisture content. The aver- 
age moisture content of the first 6 feet is usually about 20 per cent 
in the spring after being fallowed during the previous summer. 
A winter-wheat crop usually reduces the moisture content of this 
layer of soil to about 9 per cent. 
CLIMATIC DATA. 
PRECIPITATION. 
Of the climatic factors influencing crop production the precipi- 
tation and its distribution throughout the year are the most important 
in the dry-farmed areas of the far West. High yields of wheat 
usually are associated with years of heavy rainfall during the growing 
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