Food for containing so and so much Nitrogen, notwith- 



_— ^_! standing its indigestible quality as a plant food. 



238 



3. Lower cost per unit of plant-food. As shown by 

 the analyses and valuations of fertilizers made by 

 different experiment stations, the so-called overhead 

 charges made by the mixers amount, on the aver- 

 age, to more than six dollars per ton. Otherwise 

 stated, the farmer who buys mixed fertilizers is 

 made to pay about six or seven dollars per ton for 

 mixing, bagging, shipping, agents' commissions, 

 profit, long credit, etc. The overhead charges tend 

 to increase the cost per unit of plant-food in all 

 fertilizers, and to a particularly marked extent in 

 the cheaper brands. Home-mixing enables the 

 farmer to secure available plant-food at a lower 

 cost per unit. 



4. More profitable returns from the use of fertilizers 

 may be secured ichen one tinderstands their com- 

 position and the functions of their single ingredients. 

 The man who takes the trouble to make himself 

 acquainted with the origin, the history and the 

 action of different fertilizers is perforce bound to 

 secure larger returns from them than the man who 

 blindly follows the experience of others. For this 

 reason the Aome-mixing of fertilizers is an educa- 

 tional factor of great importance. The farmer who 

 does his own mixing is bound to observe the effect 

 of season, of crop and of rotation. He is bound to 

 learn something of the particular influences of 

 Nitrogen, of phosphoric acid and of potash. In 

 the course of time he is led to experiment for him- 

 self, with different mixtures, proportions and 

 methods of application, and by doing all these 

 things he becomes more skilled and successful in the 

 business of crop production. 



The opponents of /wrae-mixing have claimed, on 

 their part, that the farmer cannot prepare mixtures as 

 uniform as those made at the factory. They have also 

 claimed that the mixtures made at the farm are more 



