FERTILIZER PRACTICE 565 



in a position to make changes that will tend to a higher 

 efficiency of the constituents. The chances are that he 

 will alter his fertilizer mixture as his rotation progresses 

 and his soil changes in fertility. 



Such arguments do not always mean, however, that 

 it pays to mix at home. As a matter of fact, in many 

 cases it does not pay, especially where only a small amount 

 of fertilizer is needed and it is impossible to cooperate 

 with other farmers. As a general rule, fertilizers should 

 be bought by the method that will give the greatest value 

 for every dollar expended. Farmers often can avail 

 themselves of the advantage of both systems by asking 

 for bids from various manufacturers on carload lots of 

 mixed goods having a certain designated composition. 

 The farmers in this case designate the carriers as well. 

 All the advantages of machinery mixing may thus be 

 gained, with the lower cost which has made home mixing 

 so popular. 



475. Fertilizers not to be mixed. — Every farmer who 

 practices home mixing should keep in mind that there 

 are certain fertilizers which should not be mixed. This 

 is due to the fact that a number of materials carry lime 

 in the oxide, the hydrate, or the carbonate form. This 

 lime, particularly the caustic forms, may react in three 

 directions, depending on the fertilizer with which it is in 

 contact : (1) in setting free ammonia, (2) in causing re- 

 version of acid phosphate, and (3) in producing a bad 

 physical condition, especially when in contact with ma- 

 terials more or less deliquescent. Van Slyke l may be 

 quoted in this regard as follows : — 



1 Van Slyke, L. L. Fertilizers and Crops, pp. 485-486. 

 New York, 1912. 



