180 



Bulletin 80 



Sample 

 No. 



3674 

 3676 



3690 



Dry matter, 

 grams 



Tops of wheat and barley irrigated 

 with water averaging 20 p.p.m. cop- 

 per 30.70 



Tops of beans, berseem, peas, onions, 

 lettuce, beets, radishes, corn, avas, ■ 

 barley, and wheat irrigated with 

 water averaging 20 p.p.m. copjjer .... 



Eoots of same (washed in 4 per cent 

 HCl) 



Cu 

 grams 



P.p.m. of 



Cu in 



dry 



material 



.000400 13.00 



27.20 .000751 27.60 



8.30 .0007.50 90.00 



In brief, even when relatively large amounts of water contain- 

 ing excessive quantities of soluble copper were applied and the 

 experiments so arranged that all of the copper remained in the 

 limited volumes of soil employed, no general injury to the plants 

 was observed, although apparently slight stimulation occurred in 

 some cases. Prolonged irrigation with such solutions M^ould be 

 required to saturate the soil to a depth sufficient to seriously 

 injure plants grown in it. 



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1 A 



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Fig. 6. — Wlieat and barley irrigated (C) with copper solutions filtered 

 through soil, and (W) with Avell water. Both show stimulated growth with 

 copper. 



