96 THE AMERICAN PEACH ORCHARD 



can be bought in the form of nitrate of soda, nitrate 

 of potash, tankage, etc., or it may be applied in barn- 

 yard manure. Certain forms are cheaper, while other 

 forms are more effective. Generally the best 

 form in which nitrogen can be bought is in 

 nitrate of soda. This is being used by all prac- 

 tical and up-to-date 'growers, and while the cost by 

 the ton is rather high, it needs to be used in only 

 small quantities. 



Nitrate of potash costs considerably more than 

 nitrate of soda, but the potash is available for plant 

 growth as well as the nitrogen, and for this reason 

 as well as for others a few growers have undertaken 

 the use of this rather rare chemical. 



Tankage is a form of nitrogen which can be used 

 in some cases. It is much less soluble than nitrate 

 of soda, and its action is, therefore, spread over a 

 longer time. It is also not so liable to be lost by 

 leaching. Barnyard manure has an excess of nitro- 

 gen, and for this reason is not generally well adapted 

 to the needs of orchard trees. However, it gives 

 splendid results with peach trees where it can be 

 supplied. On most fruit farms it is not available in 

 sufficient quantities for orchard requirements, and 

 on general farms it will often do more good applied 

 to other crops, leaving the peach trees to be supplied 

 their quota of nitrogen in the form of tankage or 

 nitrate of soda. 



The most common form for phosphoric acid is 

 acid phosphate. This is known everywhere in the 

 fertilizer trade, and is satisfactory for use on peach 

 orchards. Its slight acidity is thought to be ob- 

 jectionable on land which is already sour. On this 

 account a good many growers prefer to use basic 

 slag (Thomas phosphate powder), which instead 

 of being acid, has some lime in it, which helps to 



