MANURES AND FERTILIZERS. 141 



long as cottonhull ash can be obtained in the present 

 quantities. Cottonhull ash is applied broadcast in the 

 spring at the time of first harrowing, at the rate of 750 

 to 1000 pounds per acre. As the ash is generally con- 

 sidered to contain about 25 per cent of potash, 750 

 pounds gives about 187 pounds of potash, and 1000 

 pounds of ash about 250 pounds of potash. 



As the fine quality of the present sulphate of potash 

 salts becomes more generally appreciated, there is a tend- 

 ency to use them instead of cottonhull ash, the only 

 reason for the abandonment of the latter being the un- 

 certainty of composition. This ash, however, is yet the 

 most popular potash supply, and it will long continue 

 to be so because the potash in it exists as the carbonate 

 of potash, which is by far the best form. Carbonate of 

 potash exerts a powerful influence on the soil through 

 its caustic properties, and this gives it a greater value 

 than an equal amount in the form of sulphate of potash. 

 Another important point is the entire absence of chlorine 

 in cottonhull ash. 



OTHER MANURIAL SUBSTANCES. 



Tobacco Stems supply both nitrogen and potash. 

 These stems must not be confused with tobacco stalks. 

 Stems are the midribs of the leaf that are discarded 

 when the leaf is cut into wrappers, or stemmed for the 

 English markets. They are largely employed in ferti- 

 lizing tobacco fields, and at one time the demand for 

 this purpose was very strong. Stems vary considerably 

 in analysis, according to the quantity of sand and water 

 present ; but they are usually a good purchase at $10 per 

 ton, but during the boom, prior to the panic of '73, they 

 sold as high as $35 a ton. Kentucky stems contain 

 about 25 per cent water, organic and volatile matter 62 

 per cent (including nitrogen 1.8 per cent), and mineral 

 matter 13 per cent, of which about 8 per cent is potash 



