REFERENCES 239 



Kainite is a mixture of crude salts containing 12 per 

 cent, potash. Wood ashes when pure contain 3 to 4 per cent, 

 potash in the form of carbonate and with the 30 per cent, 

 lime, usually as carbonate, make not only an available potash 

 fertilizer but a good neutralizer of soil acids. Kelp and 

 alunite are low grade potash materials found in the United 

 States, but not yet of commercial importance. Tobacco 

 waste is an excellent low grade fertilizer containing also 

 small amounts of nitrogen and phosphoric acid. 



REFERENCES 

 See references at end of Chapter VIII. 



