MANUKE, YIELD AND SOLUBLE SALTS IN SOILS. 



45 



Changes in amounts of nitrates, expressed as .2V O 3 , after fifty days. 



From this table it will be seen that in the extremely sandy 

 type of soil the addition of lime alone allowed the rate of nitri- 

 fication to exceed that which occurred in two of the other types 

 to which only lime was added, and also that the lime materially 

 increased the rate of nitrification in them all. The increase 

 during the fifty days over that present in the soil at the start, 

 for the six types, was enough to amount to 286, 323, 336, .104, 

 269, and 490 pounds per acre in the surface foot, taking the 

 mean weight of the soil at 3,000,000 pounds, and stating the 

 amounts in the order in which the soils are named in the table. 

 It is noteworthy, too, that the lime alone had a greater influ- 

 ence in stimulating nitrification in the Sandhill type than did 

 the 10 tons of stable manure alone, while in the case of the 

 Pocoson neither the lime nor the manure alone, nor the two 

 combined, stimulated the rate of nitrification in as marked a 

 way when compared with the rate which was maintained in the 

 same untreated soil, which, however, was far higher than that 



