Location, Exposure, Soils, and Windbreaks 23 



land where there is a free downward movement of water, 

 and that the reclamation of alkali land, where,,black alkali 

 is not present, is largely, if not entirely, a question of 

 drainage. 



But little can be said here on the practice of drainage 

 where irrigation is practiced, for the reason that an en- 

 gineer should usually be consulted. The problems are 

 quite different from those that are involved in the humid 

 states. 



It has long been the notion that many crops cannot be 

 successfully grown in soil strongly impregnated with these 

 salts. This would be true with black alkali, but after 

 many years' study of Colorado soils and a great many an- 

 alyses of soils from all parts of the state, Dr. Headden has 

 never been able to find more than a trace of this substance. 

 Moreover, he finds that all of our common vegetables, 

 orchard and farm crops, thrive in soils that contain as high 

 as 4.69 per cent, or 160,000 pounds per acre, of soluble 

 white alkalies in the first foot of soil. 



We may therefore safely conclude that alkali is respon- 

 sible for little or no damage in this region. But where it 

 collects in excess, we may be sure of the presence of free 

 water. Alkali, then, is a question of seepage, and the 

 death of trees and crops on such land is due, in a large 

 measure at least, to water. 



Soil Surveys 



It should be mentioned here that the Bureau of Soils of 

 the Department of Agriculture is doing a valuable work 

 in making surveys of soils, although these surveys are yet 

 confined to relatively few regions. This work comprises 



