FERTILIZING 



[03 



Potassium. Some potassium salts are necessary for every living 

 cell. They seem to be especially essential to starch formation. 

 Potash also seems to be connected with protein formation — 

 which may be a similar process — and with protein accumula- 

 tions. Those parts in which carbohydrates are transported are 

 also reported from many sources to be relatively rich in potash, 

 though this does not prove conclusively any vital connection. 



Fir.. 45. No fertilizer used 



These trees, adjoining those in the preceding figure, received nothing and produced 



156 bushels per acre in 1909. Variety, Baldwin. Compare with Fig. 44. (After Pennsylvania 



State College) 



Under normal conditions potash is likely to be of special impor- 

 tance as a fertilizer where carbohydrates are the important ele- 

 ment in the crop ; for example, sugar beets, mangels, and probably 

 fruits. 



There is a difference of opinion as to the relation of potash to 

 the maturing of the plant, some maintaining that it hastens matu- 

 rity and others that its usual effect is to prolong growth. Those 

 holding the latter view consider it especially effective on the lighter 

 soils and in dry seasons. The plant habit of closing up growth 

 on the occurrence of malnutrition of any sort probably accounts 



