POTASH FERTILIZERS 97 



found to exist. That is the maturity of these crops is hastened 

 by a supply of potash. 



Potash Helps to Neutralize Plant Acids. — Many plants contain 

 acids ; for example, in the grape there is tartaric acid ; in the 

 apple, malic ; in the orange, citric ; and potash helps to neutralize 

 these plant acids and form acid salts. 



Potash Sometimes Checks Insect Pests and Plant Diseases. — 

 Experiments show that certain forms of potash are distasteful 

 to some insects and tend to check their ravages. Potash seems 

 to make plants better able to resist attacks of certain fungi, es- 

 pecially when soils are deficient in this constituent, by producing 

 a stronger and more vigorous growth.* 



