USE OF POTASH FERTILIZERS 203 



■ Sulfate of Potash. — This is another product derived from crude 

 potash salts. It is not so generally used as the muriate. This 

 fertilizer is likewise all soluble in water. 



Kainit is a crude potash salt, unprepared except by grind- 

 ing. It is water soluble, and is used mainly in the making of 

 mixed fertilizers. i 



Wood ashes vary in the amount of potassium they contain. 

 Thoroughly leached ashes are of little or no value as a potash fertil- 

 izer. Hardwood ashes are generally richer in potassium than those 

 of soft woods. Woods burned at high heat produce ashes much 

 lower in potassium than when burned at low heat, as in a kitchen 



, Fig. 134. — Tobacco stems are a good potash fertilizer. ^ - 



range. In addition to potash, wood ashes contain from fifty to 

 seventy per cent carbonates of lime and magnesia. 



Use of Potash Fertilizers. — Peat, muck and sands are soils 

 particularly in need of potash fertilizers. Though the heavier 

 soils contain an abundant supply of potassium, yet some of them 

 respond to potash treatment. Crops demanding an abundant 

 supply of potassium are: Sugar beets, clovers, alfalfa, cabbage, 

 tobacco, turnips and corn (Figs. 135 and 136). 



For most soils needing potassium, muriate of potash is suitable 

 and the cheapest. From 100 to 200 pounds to the acre per year, 

 applied broadcast, is the usual apphcation of either the muriate 

 or sulfate for corn, turnips, potatoes and clover; and from 200 to 

 300 pounds for onions, cabbage and sugar beets. 



Certain results seem to indicate that sulfate of potash produces 

 a better quality of potatoes and tobacco than the muriate. Other 

 results show that when soil conditions are right as regards car- 



