10 



Phosjyhoric acid. — Plain superphosphate contains about sixteen 

 per cent of phosphoric acid. This is usually applied at the rate of 

 from two to three hundred pounds j^er acre. There are also several 

 brands of bone fertilizers. These are sold as " treated " and 

 " untreated." The untreated varieties give up phosphoric acid very 

 slowly. The treated, on the other hand, are more or less imme- 

 diately available. 



The gist of the whole matter of fertilizing orchards consistently 

 and sufficiently may be expressed as follows: Luxuriant growth 

 probably means abundant nitrogen. Stunted growth calls for nitro- 

 gen or water, or both. Fruit deficient in color and flavor suggests 

 the freer use of phosphoric acid and potash ; but without humus 

 in the soil, the use of commercial fertilizers may be an extravagant 

 if not useless practice. 



The following bulletins on orcharding have been issued by the 

 Cornell Agricultural Experiment Station, copies of which are avail- 

 able : 72, " The Cultivation of Orchards ; " 102 and 103, " General 

 Observations on the Care of Fruit Trees and Soil Depletion ;" 153, 

 " Impressions of Fruit Growing." 



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