CHEMICAL COMPOSITION OF ARID AND HUMID SOILS 65 



products of these chemical changes are likely to accu- 

 mulate in the soil because of the absence of sufficient 

 moisture to leach them away. (See page 307.) Their 

 presence is evidenced by incrustations on the particles 

 either at the surface or in the mass of the soil. For this 

 reason, the unfavorable conditions which would tend 

 to result from the coarser grade of the material is more 

 than offset by the large amounts of readily soluble 

 elements present. These differences are well illustrated 

 by the following table, compiled by Hilgard from the 

 results of many acid analyses in the two regions. All 

 soils derived from limestone are excluded. 



Table VIII 



Chemical Composition of Arid and Humid Soils 



Strong Hydrochloric Acid Analyses 



E 



