Cultural Experiments 



181 



CULTURAL EXPERIMENTS 



Pot Cultures with Treated Soils 



Pot cultures of corn, beans, and squash were also grown in 

 soils containing copper in the form of precipitated carbonate 

 (Cu(OH)2.CuC03), finely powdered (100-mesli) chalcocite or 

 sulphide ore, and finely powdered chrysocolla or silicate ore. 

 Large glazed stone jars containing thirty-eight pounds of soil 

 were used. Effects on growth were observed and the copper 

 content of tops and of root systems was determined. The follow- 

 ing tabulations relate to the work done in this direction, the state- 

 ment showing the copper content of corn, bean, and squash plants 

 expressed in parts per million of copper in dry matter. 



Containing traces of copper, .0025%. 



