The Busy Woman's Garden Book 



commonly and most economically derived from 

 tankage and dried blood — by-products of slaugh- 

 ter-houses — dried fish, and refuse from fish can- 

 neries and cottonseed meal; they contain, ap- 

 proximately — in dried blood, ten to fifteen per 

 cent.; tankage, seven to nine; dried fish, seven 

 to eight; cottonseed meal, six to seven per cent. 

 These decay rapidly when added to the soil and 

 are particularly valuable when applied to light 

 soils, where nitrates or ammonia leach too rap- 

 idly and should not be applied until the crops 

 are up and growing. They make available dur- 

 ing their processes of fermentation the phosphoric 

 acid and potash already present in the soil. Sul- 

 phate of ammonia, containing about twenty per 

 cent, of nitrogen is a valuable chemical form 

 in which to secure nitrogen as it does not leach 

 from the soil as nitrate of soda does and so can be 

 made available by the plant without loss. 



Phosphoric acid is found commercially in the 

 form of superphosphates; these come from phos- 

 phate rocks and are first ground, then treated 

 with sulphuric acid. Bone is rich in phosphoric 

 acid and is a very excellent form in which to sup- 



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