1917] Forbes: Irrigation Effects of Copper Compounds Upon Crops 433 



Fig. 7. — Bean cultures groAvn in soils containing copper as precipitated 

 carbonate, from none to 1.5 per cent Cu. 



Containing traces of copper, .0025%. 



Fig. 8. — Corn cultures grown in soils containing copper as precipitated car- 

 bonate, from none to .2 per cent Cu. 



