CROPS AND SOIL IMPROVEMENT 



finely pulverized pure limestone would cost unless he 

 knows that the content of fresh burned lime is high. 



The element with which we are concerned in any 

 of these forms of lime is calcium. It is the base 

 whose union with the acids destroys the latter. 

 It should be obvious that the addition of water 

 to stone-lime, which adds weight and causes 56 

 pounds of the stone-lime to become 74 pounds of 

 hydrated lime, adds no calcium. Likewise the 

 change to the air-slaked condition adds no calcium, 

 but again adds weight. 



The Kind to Apply. If a soil contains free 

 acid, the amount of calcium needed is definite. 

 The form of lime that can supply the need in that 

 particular field at least expenditure of money and 

 trouble is the one to be selected. A ton of stone- 

 lime, or pulverized lime, can correct as much acid 

 as 2640 pounds of hydrated lime or 3570 pounds of 

 pulverized limestone, if all the original material 

 was pure. 



In other words, if the value of a given weight 

 of pulverized limestone is placed at 100, the value 

 of the same weight of hydrated lime would be 132 

 and the value of stone-lime would be 180, when 

 each was finely divided and distributed through- 

 out the surface soil. 



[26] 



