SOURCES AND USE OF POTASH SALTS 



145 



of potash, sulphate of potash, double sulphate of potas- 

 sium and magnesium, double manure salts, and potas- 

 sium-magnesium carbonate. 



104. The Functions of Potash. Potash in the soil 

 favors the formation of the carbohydrates, such as starches, 

 sugars, and cellulose in the plant. It is very beneficial 



FIG. 57. Sweet potatoes grown on the same soil as those of Fig. 55 

 but fertilized with potash, phosphoric acid and nitrogen. 



to such root crops as mangolds, sugar-beets, Irish potatoes, 

 and sweet potatoes. It produces marked influences on the 

 growth of leguminous crops, not only with respect to 

 yield, but also with respect to the relative proportion 

 of the legume to the other herbage. Potash induces the 

 healthy development of the leaf and the stalk, and is 

 especially beneficial to grasses. When applied in large 

 quantities, potash lengthens the growing season of the 



