Food for }ynf plants can never use other kinds of food without Nitrate. 



^" ^ Plants must have them all to develop in perfection. 



4 Nitrate Nitrate (Nitrogen) is the kind that is nearly 



Nearly Always ^^^^^.^ t/^^^"^', ^^^ question that pre- 



Deficient sents itself to the farmer, gardener and fruit 



growler is, How can I supply my plants with 

 Nitrogen, phosphoric acid and potash, in the best forms and 

 at the least expense F We v^^ill try to throw some light upon 

 this question in the following pages. We will take first, 



Phosphoric Acid. '^^^^.^ ^'^ ^^'^^ principal sources of phos- 

 phoric acid, namely, bones and rock 

 phosphate and Thomas Slag Phosphate. Of these, the 

 rock phosphate is the cheapest source. A prevailing im- 

 pression exists that superphosphate made from rock phos- 

 phate is not as good as that made from bones. It has been 

 shown by many experiments that this idea is entirely with- 

 out foundation. What the plants want is available phos- 

 phoric acid, and it makes little or no difference from what 

 source it is derived. 



The largest deposits of rock phosphates exist in South 

 Carolina, Florida and Tennessee. These beds of phosphate 

 are supposed to be composed of the petrified bones and 

 excrements of extinct animals. When this substance is 

 ground and mixed with a sufficient quantity of sulphuric 

 acid, the larger part of the phosphoric acid which it contains 

 becomes soluble in water, and hence available as plant 

 food. This fact was one of the greatest agricultural dis- 

 coveries of the age. 



When the rock phosphate is thus treated with sulphuric 

 acid, it becomes what is commercially known as superphos- 

 phate, or acid phosphate. The same is true if ground bone 

 is treated in the same way. Good superphosphate contains 

 14 per cent, of soluble phosphoric acid. 



The cheapest sources of potash are muriate 

 of potash and unleached wood ashes, which 

 contain from 3 to 5 per cent, of potash in the form of car- 

 bonate. They also contain from i to 2-2- per cent, of phos- 

 phoric acid. They are worth, usually, as plant food, from 

 ^7.00 to $11.00 per ton. 



Nitrate is the most important and effective 

 element of plant food, and at the same time, 

 as stated, is the one that is generally deficient in the soil. 



