New York Agricultural Experiment Station. 95 



or reduced in quantity. It was then suggested that soil analysis 

 should form the basis of determining the needs of the soil in differ- 

 ent croi^s, but this failed to produce satisfactory results. The 

 formulas at present used by many have been based, in part, upon 

 the composition of the plant and, in part, upon the actual field-tests^ 



The amount of nitrogen called for by analysis of plants is gen- 

 erally reduced, because we can depend upon the soil to furnish a 

 considerable amount. In case of leguminous crops, the amount of 

 nitrogen which we need to supply can be reduced to a small fraction 

 of what the plant will use, because such crops can draw their main 

 supply of nitrogen from the air. 



The amount of soluble phosphoric acid is originally increased 

 above what plant analysis calls for, because the solubility is more or 

 less decreased after the fertilizer comes into contact with the soil. 



The formulas given in the pages following have been drawn 

 from such various sources as could be considered reliable. 



In will be noticed that, in giving the amount of fertilizer material 

 to put on one acre of land, a variable rather than a fixed amount is 

 given. To illustrate, instead of prescribing 100 pounds of nitrate of 

 soda for a certain crop, we give the amount as ^' 100 to 200 pounds." 

 This means that, if the land is in good condition, 100 pounds may 

 answer, but if in poor condition, more should be used up to 200 

 pounds. Thus, it will be seen that even with the most specific 

 directions that can be given, much must be left to the individual for 

 experiment. 



The materials which are given for use in the following pages are 

 assumed to have a fairly definite composition and our 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) Sulphate 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 applica- 

 tion ; also containing 4 per cent, of nitrogen. 



Whenever hone-meal is used in a inixture^ allowance should he 

 make f 01' its nitrogen and so much less of other forms of nitrogen- 

 materials used. 



