180 SOILS AND FERTILIZERS 



sugar beets and potatoes. On cereals, legumes and grasses 

 the muriate may be used without causing any injury, provided 

 it is not brought in contact with the seed. 



Comparatively pure forms of both muriate and sulfate of 

 potash are on the market. The former contains about 50 

 percent of potash, and the latter about 48 to 50 percent. The 

 sulfate is more expensive, but the muriate is equally good, 

 except on the rather small number of crops that are injured 

 by it. . 



The mineral produced in largest quantity by the Stass- 

 furt mines is kainit, consisting of sulfate of potash and 

 muriate of magnesia. It contains from 12 to 20 percent 

 of potash. It has the same effect on crops as has the muri- 

 ate of potash. 



Kainit should not be drilled with the seed of any crop 

 for when placed in direct contact with the seed injury 

 may result. It is a wise precaution to apply the kainit a 

 week or more before planting, if a heavy application is to 

 be made. 



232. Wood ashes. — The principal supply of potash in this 

 country at one time was wood ashes. With the diminished 

 consumption of wood as fuel, this source of potash has fallen 

 off. Now wood ashes are only an occasional supply. In 

 addition to potash, wood ashes furnish considerable lime* and 

 a little phosphoric acid„ There is no muriate present and 

 hence no injurious effect on plants, but it should not be 

 brought directly in contact with seeds. 



Unleached wood ashes contain 5 to 6 percent of potash, 

 2 percent of phosphoric acid and 30 percent of lime. Leached 

 wood ashes have only about 1 percent of potash, 1^ percent 

 of phosphoric acid and 28 to 29 percent of lime. The un- 

 leached ashes are the more valuable. 



Wood ashes are not only an excellent potash fertilizer, 

 but are also useful to counteract acidity in soils, for which 



