Tillage, Fertilizing and Rotation 107 



prevailing prices of the ingredients and comparing this 

 cost plus labor of mixing with the manufacturers' price 

 for a ready-mixed product of the same analysis, the 

 economy of home-mixing could be determined. Some 

 soils would, perhaps, require no nitrogen at all, in which 

 case the calculation for the other two elements would 

 be made exactly as before and the deficiency in making 

 a ton would be made up by the use of a filler. Often 

 in buying ready-mixed fertilizers, the producer has to 

 pay freight on a " filler " which is of comparatively no 

 value as a fertilizer. 



Mixtures adapted to the growing of sweet potatoes on 

 most soils may be mixed in the following proportions : 



1000 pounds of 16 per cent acid phosphate 

 600 pounds of cotton-seed meal 

 400 pounds of sulfate of potash. 



Total, 2000 pounds. 

 200 pounds of sulfate of ammonia about 25 per 



cent pure 

 200 pounds of dried blood 

 1200 pounds of acid phosphate about 10 or 12 per 



cent pure 

 400 pounds of muriate or sulfate of potash about 

 50 per cent pure 



Total, 2000 pounds. 



This last mixture should analyze about 4 per cent 

 nitrogen, 6 per cent phosphoric acid and 10 per cent 

 potash. The nitrogen may be left out or reduced. 



What fertilizer to apply. 



It is impossible to give any specific fertilizer ration 

 best to use on a crop of sweet potatoes. Even a chem- 



