SUMMARY ON DRY-FARM SOILS 73 



leaching by downward drainage is very small in 

 countries of limited rainfall. 



Further, arid soils show no real difference between 

 soil and subsoil; they are deeper and more perme- 

 able; they are more uniform in structure; they 

 have hardpans instead of clay subsoil, which, how- 

 ever, disappear under the influence of cultivation; 

 their subsoils to a depth of ten feet or more are as 

 fertile as the topsoil, and the availability of the 

 fertihty is greater. The failure to recognize these 

 characteristic differences between arid and humid 

 soils has been the chief cause for many crop failures 

 in the more or less rainless regions of the world. 



This brief review shows that, everything considered, 

 arid soils are superior to humid soils. In ease of 

 handling, productivity, certainty of crop-lasting 

 quality, they far surpass the soils of the countries 

 in which scientific agriculture was founded. As 

 Hilgard has suggested, the historical datum that the 

 majority of the most populous and powerful histor- 

 ical peoples of the world have been located on soils 

 that thirst for water, may find its explanation in the 

 intrinsic value of arid soils. From Babylon to the 

 United States is a far cry ; but it is one that shouts 

 to the world the superlative merits of the soil that 

 begs for water. To learn how to use the "desert" 

 is to make it "blossom like the rose." 



