94 Fertilizers 



meadow lands, as well as for certain potash-consuming 

 crops, as potatoes, tobacco and roots, since these soils are 

 very deficient in this element, and the plants mentioned 

 require it in larger proportion than do others. In fact, 

 it is believed by many careful observers and the belief 

 has been substantiated in large part by experiments 

 already conducted that the average commercial fer- 

 tilizer does not contain a sufficient amount of this element. 

 It is a particularly useful constituent element in the build- 

 ing up of worn-out soils, because contributing materially 

 to the growth of the nitrogen-gathering legumes, an 

 important crop for this particular purpose. 



Forms of potash. 



Potash, as has already been stated in the discussion of 

 phosphoric acid and nitrogen, exists in various forms, but 

 it differs from the other elements in that its chemical form 

 or combination seems to exert but relatively little influ- 

 ence upon the availability of the constituent. For exam- 

 ple, it may be in the form of a muriate or chlorid, of a 

 sulfate or of a carbonate, and while there is a difference in 

 the diffusibility of these different compounds, that is, 

 a difference in the rate at which they will distribute in the 

 soil before becoming fixed, there seems to be very little 

 difference in the rate of the absorption of the potash by the 

 plant. Nevertheless, the form of potash must be ob- 

 served, because of the possible influence that the substances 

 with which it combines may exert in reducing the market- 

 able quality of the crop to which it is applied. This 

 influence has been very distinctly observed, particularly in 

 the growing of tobacco, sugar-beets and potatoes, and it 

 has been shown that the potash in the form of a chlorid 

 (or muriate) does exert a very deleterious effect, especially 



