272 NATURE AND PROPERTIES OF SOILS 



The same bases are not always absorbed in the same propor- 

 tion by different soils; one soil may have a greater absorp- 

 tive power for potassium, while another may retain relatively 

 more ammonia. They seem to be somewhat interchangeable, 

 as any absorbed base may be released by a number of others 

 in solution. The absorptive power of a soil for certain bases 

 is reflected in the composition of the drainage water from the 

 soil. The latter varies with the soil, and a soluble fertilizer 

 applied to one soil will have a different effect on the composi- 

 tion of drainage water than if applied to another soil. This 

 is well illustrated from lysimeter experiments by Gerlach l 

 at Bromberg. Several soils were used, a portion of each being 

 fertilized and unfertilized respectively. The lysimeters were 

 1.2 meters deep and contained 4 cubic meters of soil. The 

 drainage water was collected and analyzed for four years. 

 The first yeai there was no crop, the second year potatoes were 

 grown, the third oats, and the fourth rye. The following re- 

 sults were obtained : 



Table LX 



AVERAGE COMPETITION OF DRAINAGE WATER IN PARTS PER MIL- 

 LION. BROMBERG. 



1 Gerlach, U., Vber die durch sickcrwasser dem Boden Entzogenen 

 Menge Wasser und Nahrstoffe; 111. Landw. Zeitung, 30 Jahrgrange, Heft 

 95, Seite 871-881, 1910. 



