56 



BIGGLE ORCHARD BOOK 



application is from 200 to 300 pounds. Sulphate of 

 potash is also thought to be a good form in which 

 to buy potash. The commercial article will analyze 

 about fifty per cent, of actual potash. 



Phosphoric acid may be obtained in the form of a 

 high-grade plain superphosphate (dissolved South 

 Carolina rock), in bone compounds, and Thomas slag. 

 The plain superphosphate contains about sixteen or 

 eighteen per cent, of phosphoric acid, and 400 to 600 

 pounds per acre is a liberal and very useful dressing 

 for bearing orchards. The bone fertilizers are always 

 valuable. Those which are untreated give up their 

 phosphoric acid slowly, unless they are very finely 

 ground. Dissolved bone gives more immediate results. 

 Thomas or basic slag has given good results in many 

 tests, but it parts with its fertility very slowly. Phos- 

 phoric acid is rather less important in fruit plantations 

 than potash, although this order is reversed in general 

 farming. 



A little lesson in fertility : The size of these blocks 

 shows the comparative quantities of soil fertility 

 (nitrogen, potash, and phosphoric acid) removed from 

 the farm by the selling of various home-grown prod- 

 ucts. The growing of wheat or beef draws heaviest 

 on the soil ; butter or fruits, lightest. Remem- 

 ber, too, that most of the fertility removed by 

 fruits is contained in the seeds or the pit, the 



