May, '14] 



GRANITIC SOIL POTASSIUM. 



27 



Table XX 



Water-Soluble Inorganic Matter 



There has not been any definite relation between the amount 

 of water-soluble material in the soil and the amount of crop pro- 

 duced on the light soil from which the data in Table XX was 

 obtained. The increased amount of soluble material has not 

 produced larger crops of apples nor better cover crops of crimson 

 clover. The unfertilized plots show approximately only two -fifths 

 as much water-soluble material as was found in the fertilized 

 plots. Other conditions being the same, it would appear that 

 beyond «, certain point there is no advantage in having a large 

 amount of water-soluble inorganic matter in the soil. From 

 the data in Table XX and from other observations, it follows that 

 the amount of water-soluble inorganic material in the plots which 

 received no fertilizer is as much as can be used to any advantage. 

 The additional amount found in the fertilized plots has not been 

 used. In the observations on grass plots on light soils, where the 

 amount of water-soluble inorganic material is increased by means 

 of phosphoric acid and potassium salts, there is practically no 

 increased production. The increased amount of water-soluble 

 inorganic material resulting from their application is not of use 

 to the plant. It is also true that any slight increase that potas- 

 sium salts produce in the water-soluble inorganic material in the 

 heavy clay soils is of no use to the plant. This must be proof 



