USING CHEMICAL MANURES INTELLIGENTLY 24! 



Computing the value. In a commercial way, nitrogen 

 is about three times as costly as phosphorus or potassium. 

 The cost of the fertilizing element varies from year to 



I'LANT FOOD I.V A HAG OK KERT1LI/.ER 



SVhen buyingf fertilizers do not make the mistake of supposing all of it is plant 

 food. As indicated above, just u small part is of any value to plants. The 

 greater part is dirt or material of no use to plants 



year, but, as a rule, nitrogen is worth fifteen cents per 

 pound and phosphorus and potassium each five cents per 

 pound. In computing relative values, bear in mind that 

 one per cent, means one pound in a hundred or twenty 

 pounds in a ton. 



It is also a good plan in computing the value of a fer- 

 tilizer to use the lowest figure representing the percent- 

 age, since that more nearly represents the true value. 

 Sliding figures are used more to deceive the purchaser 

 than to help him or to give him a larger quantity at the 

 cost of a smaller amount. 



In order to show the process of computing the value of 

 a fertilizer, let us take a problem for the purpose of find- 

 ing the plant-food value of a ton of fertilizer. Here is the 

 problem : 



What is the money value of the plant food in a fertilizer 

 containing 1.95 per cent, of ammonia. 7 to 8 per cent, of 



