HOME MIXING 123 



percentage or pounds per hundred. In the above analysis slightly 

 simplified, one is the total nitrogen; nine is the total phosphoric 

 acid and one is the total potash in each hundred pounds of the 

 mixture. This would be expressed 1:9:1. A higher grade fer- 

 tilizer might be 3:10:4. To determine the money value of a ton 

 when the analysis is given a verification should be made in the 

 formula itself, and the figures for the available constituents must 

 be substituted for the total constituents, so far as known. The 

 analysis will usually show this at least for the phosphoric acid. 

 If a 3:10:4 formula is corrected to read 3:9:4, then the ton value is 

 determined by multiplying each of these by twenty (the number 

 of hundred weight in a ton) , and then multiply each by the average 

 market value per pound. That is multiplying the nitrogen con- 

 tent by twenty, the available phosphoric acid by six and the 

 potash by six. The sixty pounds of nitrogen in a ton equals $12; 

 the one hundred and eighty pounds of phosphoric acid is valued 

 at $10,80, and the hundred pounds of potash equals $6.00, making 

 a total of $28.80. 



Home Mixing. It has long been the custom in European 

 countries, such as Germany and England, to practice the home 

 mixing of commercial fertilizers. American farmers have probably 

 not understood so well the scientific principles involved in fertiliz- 

 ing the soils, and there is comparatively much less home mixing 

 in America. Those farmers who practice it are able to save in sev- 

 eral ways: (1) They are able to secure the raw materials which 

 they know to be well suited to their own soils and crops. (2) They 

 are able to avoid the use of such low grade materials or fill-in 

 materials which are, in effect, of little or no benefit to the soils. 

 (3) They are able to save on the cost of freight and the amount of 

 material hauled for the same amount of plant food. (4) They 

 are able to save much in actual cost of each year's production. 



There is no secret about mixing. The amount of material 

 suitable to use in various home -mixed fertilizers for different 

 crops is published by a number of experiment stations. Figure 82 

 indicates what ingredients may be mixed before they are applied 

 and those which should not be thus mixed. 



FIELD AND LABORATORY EXERCISES 



1. Depth of Plowing. When plowing is being done in the vicinity, or at 

 home, have a ruler handy to take several measurements of the depth of the 

 furrow on the landbar side. This will help to gain a correct impression of the 

 depth of plowing at sight. In the bottom of the furrow, dig with a spade and 



