INJURY TO CROPS AND SOIL BY WASHOE PLANT. 



33 



seedlings are killed in a solution containing 1 part of copper per 

 808,846 parts of water. Johnson, in his work entitled How Crops 

 Grow, says : " The soluble compounds of copper, arsenic, and lead 

 are very injurious to plant life, unless very highly diluted." Other 

 plant physiologists in their works confirm Johnson's statement. 

 Harter ^^ says : " In the case of many plants one of the most toxic 

 substances known is copper, and it is more than likely that it is 

 present in much of the Avater which experimenters have found to be 

 injurious. Coupin states that one part of copper to 700,000,000 of 

 water is sufficient to retard the root growth of wheat seedlings. A 

 mere trace of copper is sufficient to retard growth in many cases." 



The writer is now conducting some experiments to determine Avhat 

 amount of soluble copper in soils is injurious to the growth of certain 

 plants. The work has not yet been completed, but the preliminary 

 data indicate that the growth of wheat and rye is interfered with by 

 the presence of 2.1 parts of soluble copper per million parts of earth 

 in one soil and by 3.5 parts of soluble copper per million parts of 

 earth in another soil. 



It would appear, therefore, from these aata that the Deer Lodge 

 Kiver, even at a distance of 16 to 18 miles below where the tailings are 

 discharged, is not fit for irrigation purposes, and Avill eventually, if 

 not at once, seriously injure land to which it is applied. 



It has been suggested that the Deer Lodge River already contained 

 so large a quantity of alkali salts that it was injurious to soil and 

 crops, even if the smelter wastes were not present. To determine 

 this question, a sample of the water was subjected to an irrigation- 

 water analysis with the following results: 



Table IX. — Composition of Deer Lodge River ivater (Serial No. Jt2U) about 

 1.5 miles heloiv ivhcre smelter waste enters. 



Determinations. 



Bicarbonic acid ion 

 Sulphuric acid ion. 



Chlorin 



Carbonic acid ion- 

 Calcium 



Magnesium 



Sodium 



Total 



Parts per 



million. 



78.73 



222.27 



19.00 



None. 



66.49 



19.69 



85.03 



441.21 



Hypothetical combination. 



Calcium bicarbonate 



Calcium sulphate 



Magnesium sulphate. 



Sodium sulphate 



Sodium chlorid 



Total- 



Parts per 



million. 



104.59 



138.00 



97.34 



69.93 



31.35 



This analysis shows that the Deer Lodge River does not contain 

 such a quantity of alkali salts as would render it unfit for irrigation 

 purposes. 



oThe Variability of Wheat Varieties in Resistence to Toxic Salts, U. 

 Dept. Agr., Bureau of Plant Industry, Bulletin 79, p. 40. 



S. 



