University of Arizona 



Agricultural Experiment Station 



Bulletin No. 80 



Reprinted from University of California Publications in Agricultural Sciences, Vol. 1, 



No. 12, being No. 4, co-operative, between other institutions and the 



University of Arizona Agricultural Experiment Station 



Root tip of corn grown in water culture and poisoned by l:200fl',000 of Cu in OuSO^ 

 solution. Copper colored red by means of potassium ferrocyanide. 

 • Red shows black in photomicrograph. X 53 diam. 



CERTAIN EFFECTS UNDER IRRIGATION 

 OF COPPER COMPOUNDS UPON CROPS 



By R. H. Forbes 



Tucson, Arizona, December 15, 1916 



