CHAPTER VIII 



POTASH FERTILIZERS 



228. Potassium an Essential Element of Plant 

 Food. Potassium is one of the three elements most 



essential as plant food. In its ab- 

 sence plants are unable to develop. 

 Oats seeded in a sterile soil from 

 which potash only was withheld 

 made the total growth shown in 

 the illustration (Fig. 32). When 

 potash is present in the soil in' 

 liberal amounts and associated 

 with other essential elements vig- 

 orous plants are produced. Potash 

 like phosphoric acid and nitrogen 

 is utilized by crops in the early 

 stages of growth. Potassium 

 does not accumulate in seeds to 

 the same extent as phosphoric 

 acid and nitrogen, but is present 

 Fig. 32. Oat plant mainly in stems and leaves, con- 

 grown without potash. S equently when straw crops are 

 utilized in producing manure the potash is not lost or, 

 as in the case of nitrogen, sold from the farm. But 

 with ordinary grain farming excessive losses of potash 

 do occur, particularly when the straw is burned and 

 the ashes are wasted. 



229. Amount of Potash Removed in Crops. In 



(12) 



