MIXTURES FOR CROPS 



as possible. Acid phosphate, basic slag, and bone 

 are chief in this group. 



2. The combination of phosphoric acid and 

 potash that is needed by soils obtaining all re- 

 quired nitrogen from clover or manure. In 

 most instances the phosphoric acid should run 

 higher than the potash, but the percentage of 

 potash should never run lower than 4. A lower 

 percentage of potash is not as profitable as a 

 higher one, provided any potash is needed. The 

 potash content should be greater than that of 

 the phosphoric acid in case of some sandy soils 

 and of some crops of heavy leaf growth, including 

 various garden crops. 



3. The so-called " complete " fertilizer that 

 supplies some nitrogen with the two other plant- 

 constituents. Such fertilizer should furnish, with 

 few exceptions, 3 per cent of nitrogen, if no more. 



Amount of Application. In common practice 

 fertilizers are not applied freely enough when they 

 are used at all. The exception to this rule may be 

 found in the case of small applications to cold 

 and inert soils to force growth in the first few 

 weeks of a plant's life. It is difficult to see how 

 80 or 100 pounds of fertilizer can affect an acre of 

 land one way or the other, but experience teaches 



[211] 



