Miscellaneous Fertilizing Materials 103 



rather general in their effect ; they contain small amounts 

 of all the essential constituents rather than large amounts 

 of one or two, and many of them are useful, because of 

 their indirect action. 



Tobacco stems and stalks. 



Tobacco stems consist of the waste stems or ribs of the 

 leaves, and parts of the leaves themselves, which result 

 from the stripping of tobacco for the manufacture of cigars, 

 or for smoking and chewing tobacco. The stalks in- 

 clude the main stem and branches of the plant. The 

 stems are frequently ground and sold as a fertilizer, and 

 the product is valuable for its nitrogen and potash the 

 nitrogen ranging in content from 2 to 3 per cent and the 

 potash from 6 to 10 per cent. They contain but small 

 amounts of phosphoric acid. The nitrogen exists in 

 both the nitrate and organic forms. The nitrate form 

 constitutes from one-third to one-half of the total nitrogen, 

 and its presence is due both to the fact that nitrogen exists 

 as such in the tobacco plant, and to the fact that saltpeter 

 (nitrate of potash) is frequently added in order to improve 

 the marketable quality of the lower grades of tobacco. 

 The potash occurs largely in the soluble form, and is free 

 from chlorids. The tobacco stalks are somewhat richer 

 in nitrogen than the stems, ranging from 3 to 4 per cent, 

 and are poorer in potash about 4 to 5 per cent of potash 

 though the forms of these two constituents are similar 

 in the case of both to those contained in the stems. Both 

 stems and stalks may be frequently obtained in the 

 vicinity of towns where tobacco manufacture is carried 

 on, and while more variable in their content of nitrogen 

 and potash than the ground stems and stalks, due largely 

 to the variations in the content of moisture, they are a 



