UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



AGRICULTURAL SCIENCES 



Vol. 1, No. 12, pp. 395-494, plates 6-9 April 7, 1917 



CERTAIN EFFECTS UNDER IRRIGATION OF 

 COPPER COMPOUNDS UPON CROPS* 



By R. H. FORBES 



CONTENTS PAGE 

 Part I. — Experimental Work 396 



Introduction 396 



Solid wastes 397 



Soluble copper compounds 399 



Distribution of copper compounds throughout the Clifton-Morenci 



mining and Gila River irrigated district 401 



Sources of copper 401 



Processes by which copjjer is added to the water supply 402 



Table of solubilities of copper compounds 403 



Copper in ores and tailings from Clifton-Morenci district 405 



Dissolved copper in river, irrigating and ground waters l)elow 



the Clifton-Morenci district 407 



Copper in soils irrigated with tailings waters 408 



Miscellaneous soils unaffected by mining detritus 410 



Copper in vegetation from upper GUa farms 410 



Copper in vegetation from other localities 411 



Copper in flesh and bones of a pig 412 



Distribution of copper in plants with root systems exposed to cop- 

 per compounds 413 



Corn plants grown in soils containing copper 413 



Water cultures 417 



Toxicity of copper solutions to plant roots in water culture 419 



Stimulation effects in water cultures 422 



Effects of soil upon toxicity of copper solutions 426 



Irrigation experiments 428 



Cultural experiments 432 



Pot cultures with treated soils 432 



Pot cultures with field soils 437 



Pot and plot cultures 439 



Field samjiles of soils and vegetation 440 



Use of copper sulphate to kill moss in irrigating ditches 443 



Physiological observations on toxic effects of copper salts 444 



Quantitative work 444 



* Paper No. 31, Citrus Experiment Station, College of Agriculture, Uni- 

 versity of California, Riverside, California. 



i^ VUkK 

 tiUlANlCAL 



