146 



FUNDAMENTALS OF FRUIT PRODUCTION 



m"ay be raised, whether this increase in growth or yield is not due to 

 indirect effects of the potash on some other factor, such as the availa- 

 bihty of phosphorus, or to the influence of other elements with which 

 potassium is combined in the fertilizer. This last suggestion receives 

 some support from the fact that in most cases when the muriate and 

 sulfate of potash have been used side by side, the sulfate has almost 

 invariably given a much more pronounced response than the muriate and 

 has often yielded positive results when the muriate has given entirely 

 negative results. 



Seasonal Distribution of Potassium. — Rather marked differences between 

 potassium and the elements already considered, in translocation, storage and 

 utilization are shown by the seasonal changes in its distribution within the plant. 



In Leaves. — Fruit buds are much richer than leaf buds in potassium con- 

 trasting with the condition presented by phosphorus. 



The potash content of fruit buds has been found to be 2.290 per cent, of the 

 dry weight in the cherry and 2.344 per cent, in the plum, while that of leaf buds 

 was 1.961 per cent, in the cherry and 2.213 per cent, in the plum.^^'^ 



The variation in the percentage content of potash in leaves during the growing 

 season is illustrated by the figures in Table 33. As with phosphorus and nitrogen 

 the percentage of potassium decreases as the leaf grows older and the absolute 

 amount present in the leaf passes through a maximum, as Table 34 shows. 



However, the decrease in the potash content of leaves during the fall is slight 

 in all fruits for which data are available and there is no decrease in the pear. The 



Table 34. — Grams of Potash in 100 Leaves '^^ 



Plum 



