HOW TO SUPPLY PLANT FOODS 



a tree. The average is taken from the trees on one acre, planted 

 thirty-five feet apart, and over a period of twenty years be- 

 tween the thirteenth and thirty-third years of their age. 



An average crop of apples from one tree removes, in round 

 numbers, eleven pounds of nitrogen, one pound of phosphoric 

 acid, and sixteen pounds of potash. The leaves with this crop 

 will contain ten pounds of nitrogen, three pounds of phosphoric 

 acid and ten pounds of potash. No figures are given for the 

 amount used in making new wood. The total for fruit and 

 leaves is twenty-one pounds of nitrogen, four pounds of phos- 

 phoric acid and twenty-six pounds of potash. 



For an acre of trees, the amounts would be something like 

 1,887 pounds of nitrogen, 310 pounds of phosphoric acid and 

 1,895 pounds of potash. The total value of these plant foods 

 taken from an acre in twenty years is about $379. To restore 

 the potash alone would require about twenty-one tons of wood 

 ashes containing five per cent of potash. To restore the nitro- 

 gen would require more than sixteen tons of a fertilizer con- 

 taining five per cent of nitrogen, or more than five tons of 

 nitrate of soda containing fifteen per cent of nitrogen. 



Another calculation by the same investigator shows the 

 amount of plant-food which you may expect the fruit and 

 the leaves to carry away in ten crops. The data follows: 



Apples Leaves Total Value 



Nitrogen 408 Ibs. 456 Ibs. 854 Ibs. $143 30 



Phosphoric Acid 38 Ibs. 126 Ibs. 164 Ibs. n 50 



Potash 728 Ibs. 441 Ibs. 1,169 Ibs. 5263 



Total value $207 43 



"One of the best sources of potash for orchards is wood 

 ashes," Prof. Bailey continues, "but this material is so often 

 weakened by leaching that it cannot be confidently recom- 

 mended. A good sample of urleached hardwood ashes should 

 contain from five to nine per cent potash, but some of the 

 commercial article does not analyze above two or three per 

 cent. Potash in this form has a trade value of four-and-a- 

 half cents per pound. To this value of potash in wood ashes 

 should also be added that of two per cent or less of phosphoric 

 acid, now worth six cents a pound, but only if your land needs 

 phosphoric acid. If it does not need that element, you cannot 

 afford to buy it. Forty to fifty bushels to the acre is considered 

 to be a good dressing of wood ashes, if it has been kept dry. 



"Muriate of potash is perhaps the best and most reliable 

 form in which to secure potash at the present time for fruits. 

 Commercial samples generally contain from 80 to 85 per cent 

 of muriate of potash, or about 50 per cent of actual potash. 

 Kainit is an impure muriate of potash, containing about 12 

 to 15 per cent potash. 



"Sulfate of potash is also thought to be a good form in which 

 to buy potash. The commercial article analyzes 50 per cent or 

 less of actual potash. Slyvinit is a lower grade of potassium 

 fertilizer. Its value, like that of other materials mentioned, 

 should be reckoned upon the amount of potash present. 



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