370 ANNUAL UECOHD OF SCIENCE AND INDUSTRY. 



facilitates particularly the growth of leguminous .crops, and 

 through them the assimilation of nitrogen. Without a plen- 

 tiful supply of potash, in available forms, full crops are im- 

 possible. 



2. The German potash salts afford at present the cheap- 

 est and most available supply of potash for fertilizers. They 

 supply also more or less of magnesia and sulphuric acid, 

 which are essential ingredients of plant-food, and sometimes 

 deficient in our soils, and of sodium and chlorine compounds, 

 which latter, though useful in diffusing the potassium through 

 the soil and rendering other plant-food of the soil available, 

 and hence often beneficial, may in certain cases be harmful. 

 The objectionable chlorine will, after a time, leach down and 

 away where it can do no harm. 



J 



3. The higher grades will be, in general, most profitable 

 for use in this country, because they furnish the most potas- 

 sium with the least admixture of inferior materials, on which 

 costs of freight and handling must be paid. The chlorides 

 (muriates) with 80 to 84 per cent, of chloride of potassium, 

 corresponding to 50 to 52 per cent, actual potash, and the 

 sulphates with TO to 80 per cent, of sulphate of potash, or 

 from 38 to 44 per cent, actual potash, are to be especially 

 recommended. Where common salt and magnesium com- 

 pounds are wanted, and kainit can be obtained cheaply 

 enough and applied long enough beforehand, it may be used 

 with profit. 



4. For potatoes, sugar-beets, or tobacco, the sulphates are 

 preferable. For other crops, or on wet lands, the chlorides, 

 which are cheaper, are equally good. And if the chlorides 

 are applied long enough before the seed is put in i. e., in 

 the fall for potatoes or beets to be planted in the following 

 spring, the ill effect of their chlorine upon the quality of the 

 crop will probably be prevented. 



5. Potash salts have proved especially useful for fodder 

 crops, as grass and rye ; for leguminous crops, as clover, 

 beans, pease, and vetches ; and for corn, potatoes, roots, to- 

 bacco, and fruits. 



G. Potash is most apt to be lacking in light, sandy, and 

 calcareous soils; in those consisting largely of vegetable 

 matters, like peat, muck-beds, and moors, where crops that 

 remove a good deal of potash (such as clover, corn, pota- 



