THE ABSORPTIVE PROPERTIES OF SOILS 353 



Fig. 56. — Curves showing the absorption of K in parts to a million by- 

 various soils from a solution containing 200 parts to a million of K. 

 The volume of the percolate is used as the abscissas. 



252. Time required for absorption. — The amount of 

 absorption depends on the time of contact between the 

 soil and the solution. While a large part of the dissolved 

 base is taken up in a short time after being placed in 

 contact with the soil, the maximum absorption is effected 

 only after a considerable period. Ammonia, according 

 to Way, reaches its maximum absorption in half an hour ; 

 while Henneberg and Stohmann 1 found that phosphorus 

 required twenty-four hours to reach the same degree of 

 absorption. 



1 Henneberg, W., and Stohmann, F. Ueber das Verhalten der 

 Ackererde gegen Losungen von Ammoniak und Ammoniaksalzen. 

 Jour, f . Landw., Neue Folge, Band 3 (Der ganze Reihe siebenter 

 Jahrgang), Seite 25-47. 1859. 

 2a 



