FERTILIZER REQUIREMENTS 63 



It is of the utmost importance in purchasing materials for these home 

 mixtures to buy only on a guaranty of composition and to insist that the 

 materials shall be of standard high-grade quality. 



Specific mixtures for different crops (Agric. Exp. Sta. Geneva, 

 N.Y., 14th Kept.). 



In the following tables (pages 64 to 77), Van Slyke gives 

 formulas for various crops as an illustration of the kinds of mixtures 

 that are ordinarily advised. He is convinced, however, that prac- 

 tically all purposes would be satisfactorily served by the use of not 

 more than a half dozen different formulas. We should work toward 

 the more or less independent handling of nitrogen, phosphorus and 

 potassium compounds, using them separately or together as special 

 conditions and the results of observation and experience may suggest. 

 This is possible, of course, only with the student farmer. For the 

 mass of farmers, the formal recipe or the commercial mixture must 

 yet form the basis of fertilizer applications. As a broad statement 

 to guide the careful farmer, Van Slyke suggests the following : — 



For leguminous crops, a formula of 1-8-10 (in the order of nitrogen, available 

 phosphoric acid and potash). 

 For cereals, 3-8-5. 



For all kinds of garden crops, 4-8-10. 

 For grass and forage crops, 4-6-9. 

 For orchards, 2-5-10. 

 For root-crops, 3-8-7. 



The materials that are given for use in the succeeding tables are 

 assumed to have a fairly definite composition, and the calculations are 

 based on the following conditions of composition : — 



(1) Nitrate of soda, 95 to 96 per cent pure, containing 16 per cent 

 of nitrogen. 



(2) Dried blood, containing 10 per cent of nitrogen. 



(3) Sulfate of ammonia, containing 20 per cent of nitrogen. 



(4) Stable manure, containing .5 per cent of nitrogen. 



(5) Bone-meal, containing 20 per cent of total phosphoric acid, 

 one-half being calculated as available during first season on application ; 

 also containing 4 per cent of nitrogen. 



Whenever bone-meal is used in a mixture, allowance should be made for 

 its nitrogen, and so much less of other forms of nitrogen-materials used. 



