INDIVIDUAL ELEMENTS 



. 149 



potassium content of the spur falls to a minimum in September. The low figure 

 for barren spurs throughout the year is noteworthy, as is also the increase in the 

 potassium content of spurs in the off year at the time when fruit buds are being 

 differentiated (June). 



In Fruit. — The data in Table 38 illustrate the increase in i-)otash content 

 accompanying fruit development. 



Table 38 

 July 27 



-Grams of Potash in 1,000 Berries of the Grape' 



J . 875 



Aug. 9 2.306 



Aug. 17 2.490 



Aug. 28 (softening) 2 . 194 



Sept. 7 4.288 



Sept. 17 4..824 



Sept. 28 5.588 



Oct. 5 6.179 



Oct. 12 (fully ripe) 4.924 



Oct. 22 (rotted) 4.317 



The leaves, fruit and seeds are the parts richest in potassium (see Table 40). 

 In most edible fruits potash comprises 30 to 60 per cent, of the total ash and the 

 absolute amounts shown in Table 39 are very considerable. 



Table 39. — Pounds of Potash in 1,000 Pounds of F'resh Fruit^^ 



Almonds 9 . 95 



Apricots 3 . 01 



Apples 1 . 40 



Bananas 6 . 80 



Cherries 2.77 



Chestnuts 3.67 



Figs 4.69 



Grapes 2.55 



Lemons 2 . 54 



Olives 9.11 



Oranges 2.11 



Peaches 3 .94 



Pears 1.34 



French prunes 3. 10 



Plums 3.41 



Walnuts 8.18 



The potash content of seeds is about the same as that of fruits, being usually 

 20 to 50 or even 60 per cent, of the total ash.^^ 



Table 40. — Potash Content of Apple Trees of Various Ages 

 (1 to 9 from Thompson,^^^ 13 and 100 from Roheris,^^'' 30 from Van Slyke^^'^) 



