SUBSTANCES REMOVED IN DRAINAGE WATER 305 



were made by Dr. A. Voelcker, and represent the mean 

 of not more than five collections made in December, 

 May and January and April during a period of two years. 

 They can not be regarded as showing accurately the 

 annual removal of salts from the soil but are still sig- 

 nificant. 



From this table it will be seen that lime is the in- 

 gredient lost in largest amount from this soil and that 

 the character of the manure applied influences this loss 

 to some extent. The sulfates of sodium, potassium, 

 and magnesium have notably increased the loss of lime, 

 as have also the ammonium salts. The loss of lime from 

 all of the manured plats was notably greater than from 

 the unmanured. 



Potash was not removed in large amount by the 

 drainage water from any of the plats. Ammonium 

 salts with superphosphate and with magnesia occasioned 

 only a slight loss of potash, as did also the absence of 

 manure. The plats receiving mineral manure alone and 

 farm manure lost the greatest quantities of potash. 



The quantity of sulfuric acid leached from the soil 

 is quite large and highly variable. It is frequently, 

 but by no means uniformly, large on those plats from 

 which lime is removed in large amounts. The plat 

 receiving farm manure lost the largest quantity of sul- 

 furic acid. 



Phosphoric acid was removed in small amounts and, 

 except in the case of the unmanured plat, those plats 

 losing the least phosphoric acid gave the largest yields. 

 The loss of phosphoric acid seems to be a matter of 

 failure on the part of the crop to utilize it, rather than 

 its liberation by any manurial substance. 



T 



