104 Fertilizers 



useful and often a very cheap source of nitrogen and 

 potash. 



These waste tobacco products are free from deleterious 

 compounds, and for this reason alone are highly valued 

 as a fertilizer for tobacco, as well as for small fruits, for 

 which they are especially useful, because of their known 

 insecticidal value. A ton of tobacco stems of good quality 

 contains nitrogen equivalent to the amount contained in 

 500 pounds of nitrate of soda, and potash equivalent 

 to the amount contained in 200 pounds of high-grade 

 sulfate of potash. They, therefore, possess a distinct 

 value as a source of these constituents. 



Tobacco salts. 



Extracts of tobacco are becoming important for in- 

 secticidal purposes. In the manufacture of these extracts 

 there are a number of by-products produced which are 

 sold for fertilizer purposes. Various names have been used 

 to designate these products. The most common are to- 

 bacco ammonia salt and tobacco potash salt. The former 

 contains about 14 per cent of nitrogen and 6 per cent of 

 potash; the latter 1 to 2 per cent of nitrogen and about 

 40 per cent of potash. In localities where this industry 

 is extensive, these salts are of more than ordinary interest 

 because the plant-food contained in them is in highly 

 available forms. The nitrogen is in the form of nitrate 

 and ammonia, and the potash is the form of sulfate free 

 from chlorid. 



Crude fish scrap. 



It frequently happens that farmers are so situated as 

 to be able to procure directly from the fishermen the fish 

 scrap from which dried ground fish is made. Very large 



