328 



SOILS. 



These figures differ widely in most respects from those 

 given for drain and river waters. Potash especially is far more 

 abundantly present in the Bonn soil solution than in the drain 

 water, and so is phosphoric acid; while lime is not widely dif- 

 ferent. Eichhorn therefore calculates that with a reasonably 

 adequate supply of water, these ingredients would fully suffice 

 for a full crop of wheat. The Chemnitz soil, on the other 

 hand, does not yield enough plant-food for more than a very 

 small crop upon the same assumptions. 



Continuous Solubility of Soil-ingredients. It seems to be 

 impossible to exhaust a soil's solubility by repeated or con- 

 tinuous leaching with water. This was demonstrated in 1863 

 and 1864 by Ulbricht * and by Schultze; 2 their general con- 

 clusions have quite lately been corroborated by King, 3 as the 

 result of extended and very careful investigations. 



Schultze experimented on a rich soil from Mecklenburg, by 

 continuous leaching with distilled water for six days, one liter 

 passing every twenty-four hours, with the following results. 



RICH SOIL FROM MECKLENBURG (Schultze.) 

 I.OOO.OOO PARTS OF EXTRACTS CONTAINED: 



It thus appears that while the first extraction removed the 

 main portion of the organic matter, the inorganic matters dis- 

 solved were not greatly diminished in subsequent leachings; 

 and that phosphoric acid continued to come off to the last. 

 The rich soil used in this case gave results corresponding in 



Vers. Stat. V. p. 207. 3 Ibid. VI. p. 41 1. 



8 Proc. Ass'n Prom. Agr. Sci. 1904. 



