214 



THE POTATO 



carbon hydrogen and oxygen, decaying or de- 

 cayed vegetable matter, dried blood, dried meat, 

 tankage, fish, garbage, tannery waste, cottonseed 

 and linseed meal, guano, animal manures. 



(2) Inorganic (chemical forms) Ammonia in 

 combination with other elements, nitrate of soda, 

 and nitrate of lime or nitrolin (a new Swedish 

 product). 



Phosphoric acid is supplied in the form of phos- 

 phates of lime, iron, and alumina. Some of the 

 materials used are bone phosphate (phosphate of 

 lime), raw bone, bone meal, steamed bone, bone 

 black or animal charcoal, bone ash, South Caro- 

 lina, Florida, Canada and Tennessee rock phos- 

 phates, iron phosphate, a by-product of the manu- 

 facture of iron phosphatic iron ores, and super- 

 phosphates (a product made by treating some of 

 the foregoing elements with acid to make readily 

 available or soluble phosphoric acid). 



Fertilizers should be purchased on a per pound 

 basis for the amounts of the elements actually 

 contained. The fertilizer that costs the most per 

 ton may be the cheapest. The following table 

 shows the relative amounts of the elements in 

 various combinations and is used in checking up 

 guarantees : 



To convert the guarantee of 



Ammonia 

 Nitrogen 

 Nitrate of soda 

 Bone phosphate 

 Phosphoric acid 

 Muriate of potash j 

 Actual potash 

 Sulphate of potash 

 Actual potash j 



into 



an 



equiv- 

 alent 



of 



Nitrogen 

 Ammonia 

 Nitrogen 

 Phosphoric acid 

 Bone phosphate 

 Actual potash 

 Muriate of potash 

 Actual potash 



Multiply 



by 



0.8235 

 1.214 

 0.1647 

 0.458 

 2.183 

 0.632 

 1.583 

 0.54 



Sulphate of potash 1 . 85 



