Superphosphates Potash 95 



on tobacco. In fact, tobacco manures should not contain 

 potash in the form of a muriate. For such crops as the 

 various clovers, Indian corn (maize) and the various 

 grasses, no particular difference has been observed, and the 

 form of potash that may be procured at the lowest price 

 per pound of the constituent is the one, other things being 

 equal, to use for these crops. 



Kainit. 



In the next place, the potash salts that may be obtained 

 are divided into two classes : first, the crude products of 

 the mines, and second, the manufactured products. Of 

 the crude products, kainit is the one more largely used in 

 this country than any other. The potash contained in it 

 is practically all in the form of muriate or chlorid. It is a 

 compound of chlorid of potassium and sulfate of magne- 

 sium associated with about 30 per cent of common rock 

 salt or sodium chlorid. It is really a mixture varying in 

 composition according to the mines from which it is ob- 

 tained. It is generally sold in its natural state for ferti- 

 lizer purposes, although a large part of the output of true 

 kainit is used in the manufacture of sulfate of potash. The 

 commercial product is guaranteed to contain 12 per cent 

 of actual potash. Because of its low content of potash as 

 compared with the manufactured products, the cost of 

 the actual potash is usually greater than in these, owing 

 to the increased cost of shipping and handling per unit of 

 potash. It is more generally used near the sources of 

 supply, rather than at a distance, unless the substances, as 

 ordinary salt, also exert a beneficial indirect influence upon 

 the soil, as is very frequently the case. It is not advisable 

 to apply it immediately preceding the planting, nor in the 

 hill or row, because of the danger to the young plant from 



