278 



THE PRINCIPLES OF SOIL MANAGEMENT 



There was apparently a much greater retention of 

 nitrates by the clay soil, as shown by a comparison of 

 the fertilized and unfertilized plats on both soils. 



Schulze extracted a rich soil by slowly leaching 1,000 



grams with pure water, so that one liter passed through 



in twenty-four hours. The extract for each twenty-four 



hours was analyzed every day for a period of six days. 



The total amounts dissolved during each period were 



as follows: 



Table XLII 



It will be noticed that the dissolved matter, both 

 organic and inorganic, fell off markedly after the first 

 extraction, which was larger on account of the matter 

 in solution in the soil water. Later extractions were 

 doubtless supplied largely from the substances held 

 by absorption and which gradually diffuse into the water 



