PLANT FEEDING. 13 



37. How many pounds of nitrogen, phosphoric acid 

 and potash in a ton of fertilizer made of equal parts of 

 ground bone, cottonseed meal, tankage, fish scrap, and 

 wood ashes? 



38. What is the percentage of nitrogen in a ton mixed 

 in this way? 



39. Of phosphoric acid? 



40. Of potash? 



INCREASING THE POTATO YIELD. 

 Mineral fertilizers were applied, practically doubling the returns. 



Important truth. No fertilizing material is wholly 

 plant food. A large part of every fertilizer is inert mat- 

 ter, known as filler. The plant food -elements are in gen- 

 eral found only in chemical or physical combination with 

 other elements which are not plant foods. Muriate of pot- 

 ash is the most concentrated of the fertilizing materials ; 

 yet in one ton of muriate of potash only 1,000 pounds is 

 actual plant food. The remainder is foreign matter, 

 which is of no value to the soil or to the plant. One must 



