32 



added, because there was present in them, when the manure 

 was added, not less than the amounts indicated in them under 

 "Xotliing added" on June 24, as given in the table, p. 29. 

 How large this denitrificalioii may have been cannot be stated. 

 It will be seen thati in the sample of the Hagerstown Clay 

 Loam to which the next to the largest amount of manure was 

 added, nitrification had exceeded denitrification by an amount 

 nearly equal to the nitrification which took place in the un- 

 manured soil. 



The large amounts of manure here used were chosen in or- 

 der to cover the outside limits of both intentional and acci- 

 dental practice, and the matter is discussed further in another 

 part of this bulletin. 



INFLUENCE OF MANURE UPON THE WATER-SOLUBLE PHOSPHATES IN SOILS. 



The amounts of phosphates which were recovered from these 

 8 soils, after having been 65 days in contact with- different 

 amounts of manure, are given in the next table. 



Amounts of phosphoric acid recovered from soils treated with 



manure. 



